feat(sfm): unified deployment timeline (deprecate deployment_records)

Phase 4.  Rebuilds the seismograph "Deployment History" + "Timeline"
sections on the unit detail page as a single derived view computed from
three sources: unit_assignments (authoritative project/location windows),
unit_history (calibration/retirement/deployed state changes), and SFM
events overlaid per assignment window (count + peak PVS + last event).

Fixes the wonky-timeline symptoms: missing entries, duplicate/contradictory
rows, and no visibility into what the unit was actually doing during each
deployment window.

Backend:
- backend/services/deployment_timeline.py: new deployment_timeline_for_unit()
  helper.  Merges UnitAssignment rows (with SFM event overlay fetched
  concurrently via httpx), UnitHistory state-change rows (filtered to
  meaningful change_types and de-noised by dropping rows where
  old_value == new_value — there's noise in legacy audit log from
  record_history() being called on every save), and synthetic "gap"
  entries between assignments >= 1 day apart.  Sorts newest first.

- backend/routers/units.py: new GET /api/units/{unit_id}/deployment_timeline
  endpoint with optional include_events=false flag.

- backend/routers/project_locations.py: assign / unassign / swap /
  update endpoints now write UnitHistory rows on every assignment
  lifecycle event.  New change_types: assignment_created,
  assignment_ended, assignment_swapped, assignment_updated.  These
  surface in the unified timeline (where the assignment row itself
  shows the structural data; the audit row is filtered out to avoid
  double-rendering).  Closes a real gap — assignment changes were
  previously invisible to any audit consumer.

- backend/migrate_deprecate_deployment_records.py: non-destructive
  migration.  Adds deployment_records.deprecated_at column.  For each
  legacy row without a matching UnitAssignment, best-effort
  synthesizes one (with the free-text location_name preserved in
  notes).  Marks every processed row.  Idempotent.  DROP TABLE
  deferred to a follow-up release.

Frontend (templates/unit_detail.html):
- Removed legacy "Deployment History" card (with Log Deployment button)
  and the separate "Timeline" card.  Replaced with a single
  "Deployment Timeline" section.
- Three entry visual styles: assignment rows (orange dot, location +
  project link, event-overlay summary), gap rows (dashed outline, idle
  day count), and state_change rows (navy dot, friendly label, old →
  new value).  Active assignments get a green dot + "active" badge.
- Existing loadUnitHistory() and loadDeploymentHistory() functions kept
  as shims that delegate to loadDeploymentTimeline(), so modal-save
  callbacks that referenced them still trigger a refresh of the visible
  section.  Legacy function bodies preserved under _legacy_*_unused
  names for archeology; not called by anything.

Verified end-to-end:
- BE11529 timeline now shows 2 entries (active assignment with 24-event
  overlay + the deployed→benched state change), compared to the previous
  noisy mix that included 6 no-op state-change rows.
- Migration ran against real DB: 1 legacy row processed (had no
  project_id, marked deprecated without backfill).
- Assign / unassign / swap / edit now leave a paper trail in
  unit_history.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend/migrate_deprecate_deployment_records.py

@@ -0,0 +1,209 @@
+"""
+Migration: deprecate the `deployment_records` table.
+
+Why:
+  The deployment-history view on the unit detail page used to render
+  from `deployment_records` — a manually-maintained table that drifted
+  out of sync with `unit_assignments` (the auto-written project/location
+  assignment table).  That caused the "wonky timeline" symptom: missing
+  entries, duplicate / contradictory rows, and a UI that couldn't tell
+  the operator what the unit was actually doing during each window.
+
+  Phase 4 of the SFM integration replaces the deployment-history view
+  with a derived timeline computed from `unit_assignments` +
+  `unit_history` + SFM event overlay.  This migration is the cleanup:
+
+  1. Adds a `deprecated_at` timestamp column to `deployment_records` so
+     we can mark rows that have been migrated.
+  2. For every `deployment_records` row that does NOT have a matching
+     `unit_assignments` row (matched by unit_id + overlapping date
+     range), synthesizes a best-effort UnitAssignment row.  The
+     free-text `location_name` from the legacy table is preserved on
+     the new row's `notes` field (we do NOT try to fuzzy-match it to a
+     MonitoringLocation id; too error-prone — operators will need to
+     reattach those manually if they want).
+  3. Marks every migrated deployment_records row with `deprecated_at`.
+
+  This migration is non-destructive: deployment_records rows stay in
+  the DB.  The actual `DROP TABLE` happens in a follow-up release after
+  one operator cycle confirms nothing relies on the legacy data.
+
+Idempotent: re-running the script is a no-op if the column already
+exists and all migratable rows have already been processed.
+
+Run with:
+  docker exec terra-view-terra-view-1 python3 /app/backend/migrate_deprecate_deployment_records.py
+"""
+
+import os
+import sqlite3
+import uuid
+from datetime import datetime
+
+DB_PATH = "./data/seismo_fleet.db"
+
+
+def migrate_database():
+    if not os.path.exists(DB_PATH):
+        print(f"Database not found at {DB_PATH}")
+        return
+
+    print(f"Migrating database: {DB_PATH}")
+    conn = sqlite3.connect(DB_PATH)
+    conn.row_factory = sqlite3.Row
+    cur = conn.cursor()
+
+    # 1. Add deprecated_at column if not present.
+    cur.execute("PRAGMA table_info(deployment_records)")
+    cols = {row["name"] for row in cur.fetchall()}
+    if "deprecated_at" not in cols:
+        print("Adding deployment_records.deprecated_at column ...")
+        cur.execute("ALTER TABLE deployment_records ADD COLUMN deprecated_at TEXT")
+        conn.commit()
+    else:
+        print("deployment_records.deprecated_at column already exists — skipping ADD COLUMN")
+
+    # 2. Find candidate rows: not-yet-deprecated deployment_records that
+    #    have no matching unit_assignments row.
+    cur.execute("""
+        SELECT id, unit_id, deployed_date, estimated_removal_date,
+               actual_removal_date, project_id, project_ref, location_name, notes
+          FROM deployment_records
+         WHERE deprecated_at IS NULL
+    """)
+    rows = cur.fetchall()
+    print(f"\nFound {len(rows)} deployment_records rows not yet deprecated.")
+
+    backfilled = 0
+    skipped_no_match_attempted = 0
+    skipped_already_in_assignments = 0
+    skipped_missing_unit = 0
+
+    for row in rows:
+        unit_id = row["unit_id"]
+        if not unit_id:
+            print(f"  ⚠ row {row['id']!r}: no unit_id, marking deprecated without backfill")
+            cur.execute(
+                "UPDATE deployment_records SET deprecated_at=? WHERE id=?",
+                (datetime.utcnow().isoformat(), row["id"]),
+            )
+            skipped_missing_unit += 1
+            continue
+
+        # Does the unit still exist?  If not, skip — we don't synthesize
+        # assignments for ghost units.
+        cur.execute("SELECT id, device_type FROM roster WHERE id=?", (unit_id,))
+        roster = cur.fetchone()
+        if not roster:
+            print(f"  ⚠ row {row['id']!r}: unit_id {unit_id!r} not in roster, marking deprecated without backfill")
+            cur.execute(
+                "UPDATE deployment_records SET deprecated_at=? WHERE id=?",
+                (datetime.utcnow().isoformat(), row["id"]),
+            )
+            skipped_missing_unit += 1
+            continue
+
+        # Check if a UnitAssignment already covers this window (any overlap).
+        # We don't try to be clever — just see if a row exists for this unit
+        # whose [assigned_at, assigned_until] overlaps the deployment window.
+        cur.execute("""
+            SELECT id FROM unit_assignments
+             WHERE unit_id=?
+               AND (assigned_at <= COALESCE(?, '9999')
+                    AND COALESCE(assigned_until, '9999') >= COALESCE(?, '0000'))
+             LIMIT 1
+        """, (
+            unit_id,
+            row["actual_removal_date"] or row["estimated_removal_date"] or row["deployed_date"],
+            row["deployed_date"],
+        ))
+        if cur.fetchone():
+            cur.execute(
+                "UPDATE deployment_records SET deprecated_at=? WHERE id=?",
+                (datetime.utcnow().isoformat(), row["id"]),
+            )
+            skipped_already_in_assignments += 1
+            continue
+
+        # No matching UnitAssignment — synthesize one.  We can't FK to a
+        # MonitoringLocation because the legacy `location_name` is free
+        # text.  Backfilled rows go in with location_id = "" (empty) and
+        # the original location_name dropped into notes for operator
+        # context.
+        if not row["project_id"]:
+            print(f"  ⚠ row {row['id']!r}: no project_id, can't synthesize unit_assignment, marking deprecated")
+            cur.execute(
+                "UPDATE deployment_records SET deprecated_at=? WHERE id=?",
+                (datetime.utcnow().isoformat(), row["id"]),
+            )
+            skipped_no_match_attempted += 1
+            continue
+
+        synthesized_id = str(uuid.uuid4())
+        synth_notes_parts = []
+        if row["location_name"]:
+            synth_notes_parts.append(f"Legacy location: {row['location_name']}")
+        if row["project_ref"]:
+            synth_notes_parts.append(f"Legacy project_ref: {row['project_ref']}")
+        if row["notes"]:
+            synth_notes_parts.append(f"Original notes: {row['notes']}")
+        synth_notes_parts.append(f"(Synthesized from deployment_records row {row['id']})")
+        synth_notes = " | ".join(synth_notes_parts)
+
+        assigned_until = row["actual_removal_date"]
+        # Don't auto-close active deployments based on estimated_removal_date.
+        status = "completed" if assigned_until else "active"
+
+        # Need a location_id to satisfy NOT NULL constraint.  Use a
+        # placeholder UUID so the FK can be cleaned up later if the
+        # operator decides to retarget the assignment to a real location.
+        # We tag this with the synthesized notes so it's discoverable.
+        placeholder_loc_id = ""
+
+        try:
+            cur.execute("""
+                INSERT INTO unit_assignments (
+                    id, unit_id, location_id, project_id, device_type,
+                    assigned_at, assigned_until, status, notes, created_at
+                ) VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+            """, (
+                synthesized_id,
+                unit_id,
+                placeholder_loc_id,
+                row["project_id"],
+                roster["device_type"] or "seismograph",
+                row["deployed_date"] or datetime.utcnow().isoformat(),
+                assigned_until,
+                status,
+                synth_notes,
+                datetime.utcnow().isoformat(),
+            ))
+            cur.execute(
+                "UPDATE deployment_records SET deprecated_at=? WHERE id=?",
+                (datetime.utcnow().isoformat(), row["id"]),
+            )
+            backfilled += 1
+            print(
+                f"  ✓ row {row['id']!r}: synthesized unit_assignment {synthesized_id} "
+                f"for unit={unit_id} project={row['project_id'][:8]}… "
+                f"({row['deployed_date']} → {assigned_until or 'present'})"
+            )
+        except Exception as e:
+            print(f"  ✗ row {row['id']!r}: failed to synthesize — {e}")
+
+    conn.commit()
+    conn.close()
+
+    print("\n────────────────────────────────────────────────────────")
+    print(f"Backfilled new unit_assignments:      {backfilled}")
+    print(f"Already covered (deprecated only):    {skipped_already_in_assignments}")
+    print(f"No project_id (deprecated only):      {skipped_no_match_attempted}")
+    print(f"Missing/orphaned unit (deprecated):   {skipped_missing_unit}")
+    print(f"\nNOTE: synthesized rows have an empty location_id and the legacy")
+    print(f"      free-text location is preserved in notes.  An operator should")
+    print(f"      retarget them to real MonitoringLocation rows if they want")
+    print(f"      events to show up on a location detail page.")
+
+
+if __name__ == "__main__":
+    migrate_database()

backend/routers/project_locations.py

@@ -30,6 +30,7 @@ from backend.models import (
     RosterUnit,
     MonitoringSession,
     DataFile,
+    UnitHistory,
 )
 from backend.templates_config import templates
 from backend.utils.timezone import local_to_utc
@@ -37,6 +38,42 @@ from backend.utils.timezone import local_to_utc
 router = APIRouter(prefix="/api/projects/{project_id}", tags=["project-locations"])
 
 
+# ── Audit log helper ──────────────────────────────────────────────────────────
+# Mirrors record_history() in roster_edit.py.  Kept local to avoid cross-router
+# imports.  The four assignment endpoints below use this to write UnitHistory
+# rows that the unit-detail deployment timeline (Phase 4) renders.
+
+def _record_assignment_history(
+    db: Session,
+    unit_id: str,
+    change_type: str,
+    *,
+    old_value: Optional[str] = None,
+    new_value: Optional[str] = None,
+    notes: Optional[str] = None,
+) -> None:
+    """Append a UnitHistory row for an assignment-lifecycle event.
+
+    change_type values used:
+      - assignment_created   — unit assigned to a location (new assignment)
+      - assignment_ended     — unit unassigned / removed (assigned_until set)
+      - assignment_swapped   — unit replaced by another at the same location
+      - assignment_updated   — assignment dates / notes edited via PATCH
+
+    Caller is responsible for db.commit().
+    """
+    db.add(UnitHistory(
+        unit_id=unit_id,
+        change_type=change_type,
+        field_name="unit_assignment",
+        old_value=old_value,
+        new_value=new_value,
+        changed_at=datetime.utcnow(),
+        source="manual",
+        notes=notes,
+    ))
+
+
 # ============================================================================
 # Shared helpers
 # ============================================================================
@@ -403,6 +440,13 @@ async def assign_unit_to_location(
     )
 
     db.add(assignment)
+    _record_assignment_history(
+        db,
+        unit_id=unit_id,
+        change_type="assignment_created",
+        new_value=f"{location.name} (project: {location.project_id})",
+        notes=form_data.get("notes"),
+    )
     db.commit()
     db.refresh(assignment)
 
@@ -448,11 +492,164 @@ async def unassign_unit(
     assignment.status = "completed"
     assignment.assigned_until = datetime.utcnow()
 
+    location = db.query(MonitoringLocation).filter_by(id=assignment.location_id).first()
+    _record_assignment_history(
+        db,
+        unit_id=assignment.unit_id,
+        change_type="assignment_ended",
+        old_value=location.name if location else assignment.location_id,
+        new_value="unassigned",
+    )
+
     db.commit()
 
     return {"success": True, "message": "Unit unassigned successfully"}
 
 
+@router.patch("/assignments/{assignment_id}")
+async def update_assignment(
+    project_id: str,
+    assignment_id: str,
+    request: Request,
+    db: Session = Depends(get_db),
+):
+    """
+    Update an assignment's date window and/or notes.
+
+    Common use case: backdate a deployment so events emitted before the
+    operator created the assignment in terra-view (e.g. a unit that was
+    physically deployed in December but only recorded in the system today)
+    get correctly attributed to the location.
+
+    Accepts JSON body with optional fields:
+      - assigned_at:    ISO datetime (or empty string to leave unchanged)
+      - assigned_until: ISO datetime, or null/"" to mark indefinite (active)
+      - notes:          string
+
+    Sets `status` to "active" when assigned_until is cleared, "completed"
+    when it's set in the past.
+    """
+    assignment = db.query(UnitAssignment).filter_by(
+        id=assignment_id,
+        project_id=project_id,
+    ).first()
+
+    if not assignment:
+        raise HTTPException(status_code=404, detail="Assignment not found")
+
+    try:
+        payload = await request.json()
+    except Exception:
+        raise HTTPException(status_code=400, detail="Invalid JSON body")
+
+    # Parse new values (None = unchanged, explicit None/"" for assigned_until = clear)
+    new_assigned_at = assignment.assigned_at
+    new_assigned_until = assignment.assigned_until
+    new_notes = assignment.notes
+
+    if "assigned_at" in payload:
+        raw = payload["assigned_at"]
+        if raw is None or raw == "":
+            raise HTTPException(
+                status_code=400,
+                detail="assigned_at is required; cannot be cleared.",
+            )
+        try:
+            # Accept "YYYY-MM-DDTHH:MM" from datetime-local inputs or full ISO.
+            new_assigned_at = datetime.fromisoformat(raw)
+        except (TypeError, ValueError):
+            raise HTTPException(
+                status_code=400,
+                detail=f"Invalid assigned_at datetime: {raw!r}",
+            )
+
+    if "assigned_until" in payload:
+        raw = payload["assigned_until"]
+        if raw is None or raw == "":
+            new_assigned_until = None
+        else:
+            try:
+                new_assigned_until = datetime.fromisoformat(raw)
+            except (TypeError, ValueError):
+                raise HTTPException(
+                    status_code=400,
+                    detail=f"Invalid assigned_until datetime: {raw!r}",
+                )
+
+    if "notes" in payload:
+        raw = payload["notes"]
+        new_notes = (raw or "").strip() or None
+
+    # Validation: end must be after start if both set.
+    if new_assigned_until is not None and new_assigned_until <= new_assigned_at:
+        raise HTTPException(
+            status_code=400,
+            detail="assigned_until must be after assigned_at.",
+        )
+
+    # Sanity: reject creating an overlap with another assignment of the SAME
+    # unit at the SAME location.  Different units at the same location can
+    # legitimately overlap during a swap window (rare but valid).
+    new_end_for_overlap = new_assigned_until or datetime.utcnow()
+    overlapping = (
+        db.query(UnitAssignment)
+        .filter(UnitAssignment.location_id == assignment.location_id)
+        .filter(UnitAssignment.unit_id == assignment.unit_id)
+        .filter(UnitAssignment.id != assignment.id)
+        .all()
+    )
+    for other in overlapping:
+        other_start = other.assigned_at
+        other_end = other.assigned_until or datetime.utcnow()
+        if new_assigned_at < other_end and new_end_for_overlap > other_start:
+            raise HTTPException(
+                status_code=400,
+                detail=(
+                    f"This window overlaps with another assignment for the "
+                    f"same unit ({other.assigned_at:%Y-%m-%d} → "
+                    f"{other.assigned_until and other.assigned_until.strftime('%Y-%m-%d') or 'present'})."
+                ),
+            )
+
+    # Capture change description for audit log BEFORE mutating.
+    old_start = assignment.assigned_at.isoformat() if assignment.assigned_at else None
+    old_end   = assignment.assigned_until.isoformat() if assignment.assigned_until else "active"
+    new_start = new_assigned_at.isoformat() if new_assigned_at else None
+    new_end   = new_assigned_until.isoformat() if new_assigned_until else "active"
+
+    # Apply.
+    assignment.assigned_at = new_assigned_at
+    assignment.assigned_until = new_assigned_until
+    assignment.notes = new_notes
+    assignment.status = "completed" if new_assigned_until is not None else "active"
+
+    if old_start != new_start or old_end != new_end:
+        _record_assignment_history(
+            db,
+            unit_id=assignment.unit_id,
+            change_type="assignment_updated",
+            old_value=f"{old_start} → {old_end}",
+            new_value=f"{new_start} → {new_end}",
+            notes=new_notes,
+        )
+
+    db.commit()
+    db.refresh(assignment)
+
+    return {
+        "success": True,
+        "assignment": {
+            "id":             assignment.id,
+            "unit_id":        assignment.unit_id,
+            "location_id":    assignment.location_id,
+            "assigned_at":    assignment.assigned_at.isoformat() if assignment.assigned_at else None,
+            "assigned_until": assignment.assigned_until.isoformat() if assignment.assigned_until else None,
+            "status":         assignment.status,
+            "notes":          assignment.notes,
+        },
+    }
+
+
 @router.post("/locations/{location_id}/swap")
 async def swap_unit_on_location(
     project_id: str,
@@ -503,6 +700,16 @@ async def swap_unit_on_location(
     if current:
         current.assigned_until = datetime.utcnow()
         current.status = "completed"
+        # If the swap is replacing a different unit, that unit's deployment ended.
+        if current.unit_id != unit_id:
+            _record_assignment_history(
+                db,
+                unit_id=current.unit_id,
+                change_type="assignment_swapped",
+                old_value=location.name,
+                new_value=f"swapped out → {unit_id}",
+                notes=notes,
+            )
 
     # Create new assignment
     new_assignment = UnitAssignment(
@@ -516,6 +723,13 @@ async def swap_unit_on_location(
         notes=notes,
     )
     db.add(new_assignment)
+    _record_assignment_history(
+        db,
+        unit_id=unit_id,
+        change_type="assignment_swapped" if (current and current.unit_id != unit_id) else "assignment_created",
+        new_value=f"{location.name} (project: {location.project_id})",
+        notes=notes,
+    )
 
     # Update modem pairing on the seismograph if modem provided
     if modem_id:
@@ -648,6 +862,108 @@ async def get_nrl_sessions(
     })
 
 
+@router.get("/vibration_summary", response_class=HTMLResponse)
+async def get_project_vibration_summary(
+    project_id: str,
+    request: Request,
+    from_dt: Optional[datetime] = Query(None),
+    to_dt: Optional[datetime] = Query(None),
+    db: Session = Depends(get_db),
+):
+    """
+    Render a small HTML partial summarising vibration-event activity
+    across every vibration MonitoringLocation in the project.
+
+    Returned to the Vibration tab of the project detail page via HTMX.
+    Fans out concurrently across all locations (which in turn fan out
+    across each location's UnitAssignment windows).  Total queries to
+    SFM = sum of assignments across the project.
+
+    404 if the project doesn't exist.  Empty-state partial if the
+    project has no vibration locations.
+    """
+    project = db.query(Project).filter_by(id=project_id).first()
+    if not project:
+        raise HTTPException(status_code=404, detail="Project not found.")
+
+    from backend.services.sfm_events import vibration_summary_for_project
+
+    summary = await vibration_summary_for_project(
+        db, project_id, from_dt=from_dt, to_dt=to_dt
+    )
+
+    return templates.TemplateResponse(
+        "partials/projects/vibration_summary.html",
+        {
+            "request":    request,
+            "project_id": project_id,
+            "summary":    summary,
+        },
+    )
+
+
+@router.get("/locations/{location_id}/events", response_class=JSONResponse)
+async def get_location_events(
+    project_id: str,
+    location_id: str,
+    from_dt: Optional[datetime] = Query(None),
+    to_dt: Optional[datetime] = Query(None),
+    false_trigger: Optional[bool] = Query(None),
+    limit: int = Query(500, ge=1, le=5000),
+    db: Session = Depends(get_db),
+):
+    """
+    Return SFM events recorded at this monitoring location.
+
+    Fans out the location's UnitAssignment rows (every seismograph ever
+    assigned to this location, active + closed), queries SFM /db/events
+    for each (serial, time-window) pair concurrently, and unions the
+    results.
+
+    Sound (SLM) locations return an empty payload — SFM events are
+    seismograph-only.
+    """
+    location = db.query(MonitoringLocation).filter_by(id=location_id).first()
+    if not location:
+        raise HTTPException(status_code=404, detail="Location not found.")
+    if location.project_id != project_id:
+        raise HTTPException(
+            status_code=404,
+            detail="Location does not belong to this project.",
+        )
+
+    # SLM locations don't have SFM events — return an empty payload rather
+    # than 404 so the frontend can render an empty state gracefully.
+    if location.location_type != "vibration":
+        return {
+            "events":           [],
+            "count":             0,
+            "stats": {
+                "event_count":         0,
+                "peak_pvs":            None,
+                "peak_pvs_at":         None,
+                "peak_pvs_serial":     None,
+                "last_event":          None,
+                "false_trigger_count": 0,
+            },
+            "assignments_used": [],
+            "location_type":    location.location_type,
+        }
+
+    from backend.services.sfm_events import events_for_location
+
+    result = await events_for_location(
+        db,
+        location_id,
+        from_dt=from_dt,
+        to_dt=to_dt,
+        false_trigger=false_trigger,
+        limit=limit,
+    )
+    result["location_type"] = location.location_type
+    return result
+
+
 @router.get("/nrl/{location_id}/files", response_class=HTMLResponse)
 async def get_nrl_files(
     project_id: str,

backend/routers/units.py

@@ -1,7 +1,7 @@
-from fastapi import APIRouter, Depends, HTTPException
+from fastapi import APIRouter, Depends, HTTPException, Query
 from sqlalchemy.orm import Session
 from datetime import datetime
-from typing import Dict, Any
+from typing import Dict, Any, Optional
 
 from backend.database import get_db
 from backend.services.snapshot import emit_status_snapshot
@@ -72,3 +72,101 @@ def get_unit_by_id(unit_id: str, db: Session = Depends(get_db)):
         "slm_serial_number": unit.slm_serial_number,
         "deployed_with_modem_id": unit.deployed_with_modem_id
     }
+
+
+@router.get("/units/{unit_id}/events")
+async def get_unit_events(
+    unit_id: str,
+    bucket: str = Query("all", regex="^(all|attributed|unattributed)$"),
+    from_dt: Optional[datetime] = Query(None),
+    to_dt: Optional[datetime] = Query(None),
+    false_trigger: Optional[bool] = Query(None),
+    limit: int = Query(500, ge=1, le=5000),
+    db: Session = Depends(get_db),
+):
+    """
+    Return SFM events for a single unit, annotated with assignment attribution.
+
+    Each event includes an `attribution` object pointing at the project/location
+    it falls into (or null if outside every assignment window).  Unattributed
+    events also carry a `nearest_assignment` field with `delta_days` so the
+    operator can see how far off the nearest assignment is — useful for
+    deciding whether to backdate the assignment to absorb the event.
+
+    Bucket filter:
+      - all (default): every event
+      - attributed:    only events inside an assignment window
+      - unattributed:  only orphan events (the diagnostic bucket)
+
+    Non-seismograph units return an empty events list.  The route does not
+    404 for SLMs/modems so the unit detail page can render the section
+    conditionally without depending on the response shape.
+    """
+    unit = db.query(RosterUnit).filter_by(id=unit_id).first()
+    if not unit:
+        raise HTTPException(status_code=404, detail=f"Unit {unit_id} not found")
+
+    if unit.device_type != "seismograph":
+        return {
+            "events":            [],
+            "count":              0,
+            "stats": {
+                "event_count":         0,
+                "unattributed_count":  0,
+                "peak_pvs":            None,
+                "peak_pvs_at":         None,
+                "peak_pvs_serial":     None,
+                "last_event":          None,
+                "false_trigger_count": 0,
+            },
+            "assignments_total":  0,
+            "device_type":        unit.device_type,
+        }
+
+    from backend.services.sfm_events import events_for_unit
+
+    result = await events_for_unit(
+        db,
+        unit_id,
+        bucket=bucket,
+        from_dt=from_dt,
+        to_dt=to_dt,
+        false_trigger=false_trigger,
+        limit=limit,
+    )
+    result["device_type"] = unit.device_type
+    return result
+
+
+@router.get("/units/{unit_id}/deployment_timeline")
+async def get_unit_deployment_timeline(
+    unit_id: str,
+    include_events: bool = Query(True),
+    db: Session = Depends(get_db),
+):
+    """
+    Return a chronological deployment timeline for a unit.
+
+    Merges three sources:
+      1. unit_assignments — authoritative project/location deployments
+      2. unit_history — state changes (calibration, retirement, etc.)
+      3. SFM events — per-assignment overlay (count + peak PVS + last event)
+
+    Replaces the legacy /api/deployments/{unit_id} (which read the
+    deprecated `deployment_records` table) and the
+    /api/roster/history/{unit_id} timeline endpoint, unifying them into
+    a single derived view.
+
+    Gaps >= 1 day between consecutive assignments are surfaced as
+    synthetic "gap" entries.
+
+    Pass include_events=false to skip the SFM event overlay (saves N
+    HTTP calls; useful for fast text-only history dumps).
+    """
+    from backend.services.deployment_timeline import deployment_timeline_for_unit
+
+    return await deployment_timeline_for_unit(
+        db,
+        unit_id,
+        include_event_overlay=include_events,
+    )

backend/services/deployment_timeline.py

@@ -0,0 +1,256 @@
+"""
+Deployment timeline service — replaces the legacy `deployment_records`-driven
+timeline on the seismograph unit detail page.
+
+Architecture:
+  - `unit_assignments` is the authoritative source for "where was this unit"
+    (one row per location/time-window).  Auto-written by the project location
+    swap/assign/unassign/update workflows.
+  - `unit_history` is the audit log for non-location state changes
+    (calibration toggles, retirement, allocation, etc.).
+  - SFM events are overlaid per assignment window to show "what was the unit
+    actually doing during this deployment" (count + peak PVS + last-event).
+
+Gaps between assignments are emitted as synthetic "gap" entries so operators
+can see when the unit was idle vs out-of-service.
+
+`deployment_records` is being deprecated; this module does not read it.
+"""
+
+from __future__ import annotations
+
+import asyncio
+import logging
+from datetime import datetime, timedelta
+from typing import Optional
+
+import httpx
+from sqlalchemy.orm import Session
+
+from backend.models import (
+    UnitAssignment,
+    UnitHistory,
+    MonitoringLocation,
+    Project,
+    RosterUnit,
+)
+from backend.services.sfm_events import (
+    SFM_BASE_URL,
+    _fetch_events_for_serial,
+    _iso_utc,
+)
+
+log = logging.getLogger("backend.services.deployment_timeline")
+
+# Don't emit synthetic gap entries shorter than this (seconds).  Avoids visual
+# clutter from a sub-second handoff during a swap workflow.
+_MIN_GAP_SECONDS = 24 * 3600  # 1 day
+
+# Per-call timeout when querying SFM for the event overlay.
+_SFM_TIMEOUT = 10.0
+_SFM_FETCH_CEILING = 5000
+
+
+# ── Public API ────────────────────────────────────────────────────────────────
+
+
+async def deployment_timeline_for_unit(
+    db: Session,
+    unit_id: str,
+    *,
+    include_event_overlay: bool = True,
+) -> dict:
+    """Build a chronological timeline for a unit.
+
+    Returns:
+      {
+        "unit_id":       str,
+        "device_type":   str,
+        "entries": [
+          {
+            "kind":        "assignment" | "gap" | "state_change",
+            "starts_at":   ISO timestamp,
+            "ends_at":     ISO timestamp | None,
+            "duration_days": float | None,
+            # — assignment-only fields —
+            "assignment_id":  str,
+            "location_id":    str,
+            "location_name":  str,
+            "project_id":     str,
+            "project_name":   str,
+            "is_active":      bool,
+            "event_overlay":  {event_count, peak_pvs, peak_pvs_at, last_event}
+                              or None if include_event_overlay=False,
+            "notes":          str | None,
+            # — gap-only fields —
+            "context":        "between assignments" | None,
+            # — state_change-only fields —
+            "change_type":    str,
+            "field_name":     str | None,
+            "old_value":      str | None,
+            "new_value":      str | None,
+            "source":         str,
+            "history_notes":  str | None,
+          },
+          ...                            # newest first
+        ],
+      }
+    """
+    unit = db.query(RosterUnit).filter_by(id=unit_id).first()
+    if not unit:
+        return {"unit_id": unit_id, "device_type": None, "entries": []}
+
+    # 1. Load assignments + their location/project lookups in bulk.
+    assignments = (
+        db.query(UnitAssignment)
+        .filter(UnitAssignment.unit_id == unit_id)
+        .order_by(UnitAssignment.assigned_at.asc())
+        .all()
+    )
+
+    loc_ids = {a.location_id for a in assignments}
+    proj_ids = {a.project_id for a in assignments}
+    loc_map = {
+        l.id: l for l in db.query(MonitoringLocation).filter(
+            MonitoringLocation.id.in_(loc_ids)
+        ).all()
+    } if loc_ids else {}
+    proj_map = {
+        p.id: p for p in db.query(Project).filter(
+            Project.id.in_(proj_ids)
+        ).all()
+    } if proj_ids else {}
+
+    # 2. Load relevant unit_history rows.  We surface state changes that
+    #    operators care about on a deployment timeline: calibration status,
+    #    retirement, deployed flag, allocation, calibration date, and the
+    #    assignment_* events we just added (those are redundant with the
+    #    assignment rows themselves, so we skip them to avoid double-rendering).
+    interesting_change_types = (
+        "calibration_status_change",
+        "retired_change",
+        "deployed_change",
+        "allocation_change",
+        "last_calibrated_change",
+        "next_calibration_due_change",
+    )
+    history = (
+        db.query(UnitHistory)
+        .filter(UnitHistory.unit_id == unit_id)
+        .filter(UnitHistory.change_type.in_(interesting_change_types))
+        .order_by(UnitHistory.changed_at.asc())
+        .all()
+    )
+
+    now = datetime.utcnow()
+
+    # 3. Optionally fetch SFM event overlay for each assignment window.
+    #    Concurrent fan-out via httpx + asyncio.gather.
+    overlays: dict[str, dict] = {}
+    if include_event_overlay and assignments and unit.device_type == "seismograph":
+        async with httpx.AsyncClient(timeout=_SFM_TIMEOUT) as client:
+            results = await asyncio.gather(
+                *(
+                    _fetch_events_for_serial(
+                        client,
+                        serial=unit_id,
+                        from_dt=a.assigned_at,
+                        to_dt=a.assigned_until or now,
+                        false_trigger=None,
+                        limit=_SFM_FETCH_CEILING,
+                    )
+                    for a in assignments
+                ),
+                return_exceptions=False,
+            )
+        for a, events in zip(assignments, results):
+            peak = None
+            peak_at = None
+            last_ev = None
+            for ev in events:
+                pvs = ev.get("peak_vector_sum")
+                if pvs is not None and (peak is None or pvs > peak):
+                    peak = pvs
+                    peak_at = ev.get("timestamp")
+                ts = ev.get("timestamp")
+                if ts and (last_ev is None or ts > last_ev):
+                    last_ev = ts
+            overlays[a.id] = {
+                "event_count": len(events),
+                "peak_pvs":    peak,
+                "peak_pvs_at": peak_at,
+                "last_event":  last_ev,
+            }
+
+    # 4. Build entries.  Start by emitting assignment rows + gap rows between
+    #    consecutive assignments, then add state-change rows from unit_history.
+    entries: list[dict] = []
+
+    for idx, a in enumerate(assignments):
+        loc = loc_map.get(a.location_id)
+        proj = proj_map.get(a.project_id)
+        is_active = a.assigned_until is None
+        ends_at = a.assigned_until or now
+        duration_days = (ends_at - a.assigned_at).total_seconds() / 86400 if a.assigned_at else None
+
+        entry = {
+            "kind":          "assignment",
+            "starts_at":     _iso_utc(a.assigned_at),
+            "ends_at":       _iso_utc(a.assigned_until),
+            "duration_days": round(duration_days, 1) if duration_days is not None else None,
+            "assignment_id": a.id,
+            "location_id":   a.location_id,
+            "location_name": loc.name if loc else None,
+            "project_id":    a.project_id,
+            "project_name":  proj.name if proj else None,
+            "is_active":     is_active,
+            "notes":         a.notes,
+            "event_overlay": overlays.get(a.id),
+        }
+        entries.append(entry)
+
+        # Gap detection: from the end of this assignment to the start of the
+        # next one.  Only emit gaps that are at least _MIN_GAP_SECONDS long
+        # so trivial sub-second handoffs during swaps don't clutter the view.
+        if idx + 1 < len(assignments):
+            next_a = assignments[idx + 1]
+            gap_start = a.assigned_until or now
+            gap_end = next_a.assigned_at
+            gap_seconds = (gap_end - gap_start).total_seconds() if gap_end and gap_start else 0
+            if gap_seconds >= _MIN_GAP_SECONDS:
+                entries.append({
+                    "kind":          "gap",
+                    "starts_at":     _iso_utc(gap_start),
+                    "ends_at":       _iso_utc(gap_end),
+                    "duration_days": round(gap_seconds / 86400, 1),
+                    "context":       "between assignments",
+                })
+
+    # 5. State changes — interleaved by timestamp.  Skip no-op rows where
+    #    old_value == new_value (an artifact of the legacy record_history()
+    #    being called on every save regardless of whether the field changed).
+    for h in history:
+        if h.old_value == h.new_value:
+            continue
+        entries.append({
+            "kind":          "state_change",
+            "starts_at":     _iso_utc(h.changed_at),
+            "ends_at":       None,
+            "duration_days": None,
+            "change_type":   h.change_type,
+            "field_name":    h.field_name,
+            "old_value":     h.old_value,
+            "new_value":     h.new_value,
+            "source":        h.source,
+            "history_notes": h.notes,
+        })
+
+    # 6. Sort newest first.  Active assignments (no end) sort by start time,
+    #    same as everything else.
+    entries.sort(key=lambda e: e.get("starts_at") or "", reverse=True)
+
+    return {
+        "unit_id":     unit.id,
+        "device_type": unit.device_type,
+        "entries":     entries,
+    }

backend/services/sfm_events.py

@@ -0,0 +1,582 @@
+"""
+SFM events service — bridge between terra-view's UnitAssignment time-windows
+and the SFM (seismo-relay) events store.
+
+Architecture:
+  1. Terra-view owns the *assignment graph*: which seismograph was at which
+     monitoring location during which time window (UnitAssignment rows).
+  2. SFM owns the *events store*: triggered waveform events keyed by
+     (serial, timestamp), forwarded from Blastware ACH by series3-watcher.
+  3. This module fans out the assignments for a given location, queries SFM
+     for the events emitted by each (serial, window) pair concurrently, and
+     unions/sorts/paginates the results.
+
+SFM remains the single source of truth for events.  Terra-view does not
+copy events into its own DB; every query hits SFM live.
+
+The events_for_location helper is also reused by Phase 3 (project-level
+roll-up) to aggregate across every location in a project.
+"""
+
+from __future__ import annotations
+
+import asyncio
+import logging
+import os
+from datetime import datetime, timezone
+from typing import Optional
+
+import httpx
+from sqlalchemy.orm import Session
+
+from backend.models import UnitAssignment, RosterUnit, MonitoringLocation, Project
+
+log = logging.getLogger("backend.services.sfm_events")
+
+SFM_BASE_URL = os.getenv("SFM_BASE_URL", "http://localhost:8200")
+
+# Per-request timeout when calling SFM /db/events.  SFM is local on the
+# docker network so this should be fast; bump if you start seeing timeouts.
+_SFM_TIMEOUT_SECONDS = 10.0
+
+# Max events we ever fetch per (serial, window) call to SFM.  Must match
+# SFM's own /db/events max limit (currently 5000).  The user-facing display
+# limit is independent — we over-fetch up to this cap so summary stats are
+# accurate, then trim the displayed list to the requested limit.
+_SFM_FETCH_CEILING = 5000
+
+
+# ── Helpers ───────────────────────────────────────────────────────────────────
+
+
+def _iso_utc(dt: Optional[datetime]) -> Optional[str]:
+    """Render a datetime in the ISO format SFM /db/events expects."""
+    if dt is None:
+        return None
+    # SFM parses naive ISO strings as UTC; strip tzinfo for consistency.
+    if dt.tzinfo is not None:
+        dt = dt.astimezone(timezone.utc).replace(tzinfo=None)
+    return dt.isoformat(sep=" ", timespec="seconds")
+
+
+def _intersect_window(
+    assignment_start: datetime,
+    assignment_end: Optional[datetime],
+    filter_from: Optional[datetime],
+    filter_to: Optional[datetime],
+    now: datetime,
+) -> Optional[tuple[datetime, datetime]]:
+    """Intersect an assignment window with the requested filter window.
+
+    Returns (effective_start, effective_end) or None if there's no overlap.
+    Open-ended assignments (assigned_until=NULL) are bounded by `now`.
+    """
+    a_end = assignment_end or now
+    if filter_from and a_end <= filter_from:
+        return None
+    if filter_to and assignment_start >= filter_to:
+        return None
+    start = max(assignment_start, filter_from) if filter_from else assignment_start
+    end = min(a_end, filter_to) if filter_to else a_end
+    if end <= start:
+        return None
+    return (start, end)
+
+
+async def _fetch_events_for_serial(
+    client: httpx.AsyncClient,
+    serial: str,
+    *,
+    from_dt: datetime,
+    to_dt: datetime,
+    false_trigger: Optional[bool],
+    limit: int,
+) -> list[dict]:
+    """Issue one /db/events call to SFM for one (serial, window) pair."""
+    params: dict[str, str] = {
+        "serial": serial,
+        "from_dt": _iso_utc(from_dt) or "",
+        "to_dt": _iso_utc(to_dt) or "",
+        "limit": str(limit),
+    }
+    if false_trigger is not None:
+        params["false_trigger"] = "true" if false_trigger else "false"
+
+    try:
+        resp = await client.get(f"{SFM_BASE_URL}/db/events", params=params)
+        resp.raise_for_status()
+    except httpx.HTTPError as e:
+        log.warning("SFM /db/events failed for serial=%s: %s", serial, e)
+        return []
+
+    payload = resp.json()
+    events = payload.get("events", []) or []
+    # Strip waveform_blob if present — it's the big per-event binary and we
+    # don't render it in the list view.  SFM returns it by default.
+    for ev in events:
+        ev.pop("waveform_blob", None)
+        ev.pop("a5_pickle_filename", None)
+    return events
+
+
+# ── Public API ────────────────────────────────────────────────────────────────
+
+
+async def events_for_location(
+    db: Session,
+    location_id: str,
+    *,
+    from_dt: Optional[datetime] = None,
+    to_dt: Optional[datetime] = None,
+    false_trigger: Optional[bool] = None,
+    limit: int = 500,
+) -> dict:
+    """Fan out UnitAssignment rows for `location_id` and union SFM events.
+
+    Returns:
+      {
+        "events":           [merged event dicts, newest first, capped at limit],
+        "count":            total events found across all windows (pre-cap),
+        "stats":            {event_count, peak_pvs, peak_pvs_at,
+                             last_event, false_trigger_count},
+        "assignments_used": [{unit_id, assigned_at, assigned_until,
+                              events_in_window}, ...],
+      }
+
+    The "events outside any assignment window" rule (Phase 1 design decision):
+    events whose timestamp falls outside every assignment window are simply
+    not fetched — we only ask SFM for events inside the intersected windows.
+    Those orphan events surface under the per-unit detail page in Phase 2.
+    """
+    # 1. Fetch all assignments (active + closed) for the location.
+    assignments = (
+        db.query(UnitAssignment)
+        .filter(UnitAssignment.location_id == location_id)
+        .filter(UnitAssignment.device_type == "seismograph")
+        .order_by(UnitAssignment.assigned_at.asc())
+        .all()
+    )
+
+    if not assignments:
+        return {
+            "events":           [],
+            "count":             0,
+            "stats":             _empty_stats(),
+            "assignments_used": [],
+        }
+
+    now = datetime.utcnow()
+
+    # 2. For each assignment, compute the effective (start, end) window after
+    #    intersecting with the requested filter range.  Drop assignments that
+    #    don't overlap the filter window.
+    fetch_specs: list[tuple[UnitAssignment, datetime, datetime]] = []
+    for a in assignments:
+        window = _intersect_window(a.assigned_at, a.assigned_until, from_dt, to_dt, now)
+        if window is not None:
+            fetch_specs.append((a, window[0], window[1]))
+
+    if not fetch_specs:
+        return {
+            "events":           [],
+            "count":             0,
+            "stats":             _empty_stats(),
+            "assignments_used": [
+                {
+                    "unit_id":        a.unit_id,
+                    "assigned_at":    _iso_utc(a.assigned_at),
+                    "assigned_until": _iso_utc(a.assigned_until),
+                    "events_in_window": 0,
+                }
+                for a in assignments
+            ],
+        }
+
+    # 3. Concurrent SFM fetches.  We over-fetch (up to _SFM_FETCH_CEILING per
+    #    window) so summary stats reflect the true peak/last/count across the
+    #    full filter window, not just what fits in the user's display limit.
+    #    The displayed event list is trimmed to `limit` after merge.
+    async with httpx.AsyncClient(timeout=_SFM_TIMEOUT_SECONDS) as client:
+        per_window_lists = await asyncio.gather(
+            *(
+                _fetch_events_for_serial(
+                    client,
+                    serial=a.unit_id,
+                    from_dt=start,
+                    to_dt=end,
+                    false_trigger=false_trigger,
+                    limit=_SFM_FETCH_CEILING,
+                )
+                for a, start, end in fetch_specs
+            ),
+            return_exceptions=False,
+        )
+
+    # 4. Build the per-assignment event counts (transparency for the operator).
+    spec_event_counts: dict[str, int] = {}
+    for (a, _start, _end), evs in zip(fetch_specs, per_window_lists):
+        spec_event_counts[a.id] = len(evs)
+
+    # 5. Union, sort newest-first, cap.
+    merged: list[dict] = []
+    for evs in per_window_lists:
+        merged.extend(evs)
+    merged.sort(key=lambda e: e.get("timestamp") or "", reverse=True)
+    total_count = len(merged)
+    capped = merged[:limit]
+
+    # 6. Compute summary stats over the full merged set (not the capped one).
+    stats = _compute_stats(merged)
+
+    # 7. Build the assignments_used report (every assignment, in chronological
+    #    order, with its event count — even ones that fell outside the filter
+    #    window so the operator sees them but with count=0).
+    assignments_used = []
+    for a in assignments:
+        assignments_used.append(
+            {
+                "unit_id":          a.unit_id,
+                "assignment_id":    a.id,
+                "assigned_at":      _iso_utc(a.assigned_at),
+                "assigned_until":   _iso_utc(a.assigned_until),
+                "events_in_window": spec_event_counts.get(a.id, 0),
+                "status":           a.status,
+            }
+        )
+
+    return {
+        "events":           capped,
+        "count":            total_count,
+        "stats":            stats,
+        "assignments_used": assignments_used,
+    }
+
+
+# ── Per-unit (cross-project) view ─────────────────────────────────────────────
+
+
+async def events_for_unit(
+    db: Session,
+    unit_id: str,
+    *,
+    bucket: str = "all",   # "all" | "attributed" | "unattributed"
+    from_dt: Optional[datetime] = None,
+    to_dt: Optional[datetime] = None,
+    false_trigger: Optional[bool] = None,
+    limit: int = 500,
+) -> dict:
+    """Return events for a unit annotated with their assignment attribution.
+
+    Unlike events_for_location (which queries SFM per assignment window), this
+    helper queries SFM for ALL events for the serial within the optional
+    [from_dt, to_dt] filter, then walks each event against the unit's
+    UnitAssignment intervals to compute attribution.
+
+    Bucket semantics:
+      - "all":          every event, attributed or not
+      - "attributed":   events that fall inside at least one assignment window
+      - "unattributed": events with no overlapping assignment (the diagnostic
+                        bucket — operator should fix assignment dates to
+                        attribute these)
+
+    Each event gets an extra `attribution` field:
+      {assignment_id, location_id, location_name, project_id, project_name,
+       assigned_at, assigned_until}                                 or None
+
+    Unattributed events also get a `nearest_assignment` field with the
+    same shape plus `delta_days` (signed; negative = event before assignment).
+    """
+    # 1. Pull all assignments for this unit (any device_type — caller has
+    #    already filtered by seismograph in the route).  Order matters: we
+    #    want the earliest-start assignment first so attribution prefers the
+    #    chronologically-first overlap when there are simultaneous active
+    #    assignments at different locations (rare but possible).
+    assignments = (
+        db.query(UnitAssignment)
+        .filter(UnitAssignment.unit_id == unit_id)
+        .order_by(UnitAssignment.assigned_at.asc())
+        .all()
+    )
+
+    # Resolve location + project names once.
+    loc_ids = {a.location_id for a in assignments}
+    proj_ids = {a.project_id for a in assignments}
+    loc_map = {
+        l.id: l for l in db.query(MonitoringLocation).filter(
+            MonitoringLocation.id.in_(loc_ids)
+        ).all()
+    } if loc_ids else {}
+    proj_map = {
+        p.id: p for p in db.query(Project).filter(
+            Project.id.in_(proj_ids)
+        ).all()
+    } if proj_ids else {}
+
+    now = datetime.utcnow()
+
+    def _attr_dict(a: UnitAssignment) -> dict:
+        loc = loc_map.get(a.location_id)
+        proj = proj_map.get(a.project_id)
+        return {
+            "assignment_id":  a.id,
+            "location_id":    a.location_id,
+            "location_name":  loc.name if loc else None,
+            "project_id":     a.project_id,
+            "project_name":   proj.name if proj else None,
+            "assigned_at":    _iso_utc(a.assigned_at),
+            "assigned_until": _iso_utc(a.assigned_until),
+        }
+
+    # 2. Fetch all events for this serial in one shot.
+    async with httpx.AsyncClient(timeout=_SFM_TIMEOUT_SECONDS) as client:
+        events = await _fetch_events_for_serial(
+            client,
+            serial=unit_id,
+            from_dt=from_dt or datetime(1970, 1, 1),
+            to_dt=to_dt or now,
+            false_trigger=false_trigger,
+            limit=_SFM_FETCH_CEILING,
+        )
+
+    # 3. For each event, walk the assignment list and find the first
+    #    overlapping window.  O(N * M) but both are small in practice.
+    for ev in events:
+        ts_str = ev.get("timestamp")
+        if not ts_str:
+            ev["attribution"] = None
+            continue
+        try:
+            # SFM returns ISO with "T" separator; tolerate both.
+            ts = datetime.fromisoformat(ts_str.replace(" ", "T"))
+        except ValueError:
+            ev["attribution"] = None
+            continue
+
+        matched: Optional[UnitAssignment] = None
+        for a in assignments:
+            a_end = a.assigned_until or now
+            if a.assigned_at <= ts <= a_end:
+                matched = a
+                break
+
+        if matched is not None:
+            ev["attribution"] = _attr_dict(matched)
+        else:
+            ev["attribution"] = None
+            # Find the nearest assignment (chronologically) for diagnostic.
+            if assignments:
+                nearest = min(
+                    assignments,
+                    key=lambda a: min(
+                        abs((ts - a.assigned_at).total_seconds()),
+                        abs((ts - (a.assigned_until or now)).total_seconds()),
+                    ),
+                )
+                # Signed delta in days from the nearest boundary
+                # (negative = event BEFORE that boundary).
+                if ts < nearest.assigned_at:
+                    delta_seconds = (ts - nearest.assigned_at).total_seconds()
+                elif ts > (nearest.assigned_until or now):
+                    delta_seconds = (ts - (nearest.assigned_until or now)).total_seconds()
+                else:
+                    delta_seconds = 0
+                ev["nearest_assignment"] = {
+                    **_attr_dict(nearest),
+                    "delta_days": round(delta_seconds / 86400, 1),
+                }
+
+    # 4. Apply bucket filter.
+    if bucket == "attributed":
+        filtered = [e for e in events if e.get("attribution") is not None]
+    elif bucket == "unattributed":
+        filtered = [e for e in events if e.get("attribution") is None]
+    else:
+        filtered = events
+
+    filtered.sort(key=lambda e: e.get("timestamp") or "", reverse=True)
+    total_count = len(filtered)
+    capped = filtered[:limit]
+
+    # 5. Stats: compute over the ENTIRE event set (not the filtered bucket)
+    #    so the unattributed_count tile is always meaningful regardless of
+    #    which bucket the operator has selected.
+    base_stats = _compute_stats(events)
+    unattributed_count = sum(
+        1 for e in events if e.get("attribution") is None
+    )
+    base_stats["unattributed_count"] = unattributed_count
+
+    return {
+        "events":             capped,
+        "count":              total_count,
+        "stats":              base_stats,
+        "assignments_total":  len(assignments),
+    }
+
+
+# ── Project-level roll-up (aggregates across all vibration locations) ─────────
+
+
+async def vibration_summary_for_project(
+    db: Session,
+    project_id: str,
+    *,
+    from_dt: Optional[datetime] = None,
+    to_dt: Optional[datetime] = None,
+) -> dict:
+    """Aggregate SFM events across every vibration location in a project.
+
+    Returns:
+      {
+        "project_id":  str,
+        "total_events": int,
+        "peak_pvs":     float | None,
+        "peak_pvs_at":  ISO timestamp | None,
+        "peak_pvs_location_id":   str | None,
+        "peak_pvs_location_name": str | None,
+        "last_event":   ISO timestamp | None,
+        "false_trigger_count": int,
+        "per_location": [
+            {"location_id", "location_name", "event_count",
+             "peak_pvs", "last_event"},
+            ...                          # sorted by event_count DESC
+        ],
+        "vibration_location_count": int,
+      }
+    """
+    locations = (
+        db.query(MonitoringLocation)
+        .filter(MonitoringLocation.project_id == project_id)
+        .filter(MonitoringLocation.location_type == "vibration")
+        .all()
+    )
+
+    if not locations:
+        return {
+            "project_id":            project_id,
+            "total_events":           0,
+            "peak_pvs":               None,
+            "peak_pvs_at":            None,
+            "peak_pvs_location_id":   None,
+            "peak_pvs_location_name": None,
+            "last_event":             None,
+            "false_trigger_count":    0,
+            "per_location":           [],
+            "vibration_location_count": 0,
+        }
+
+    # Fan out across locations.  Each call internally fans out across that
+    # location's UnitAssignment rows, so this is a nested fan-out.  Both
+    # tiers happen concurrently because asyncio.gather + httpx pool.
+    results = await asyncio.gather(
+        *(
+            events_for_location(
+                db,
+                loc.id,
+                from_dt=from_dt,
+                to_dt=to_dt,
+                false_trigger=None,
+                limit=1,    # We only need stats; events list itself is ignored.
+            )
+            for loc in locations
+        ),
+        return_exceptions=False,
+    )
+
+    per_location: list[dict] = []
+    total_events = 0
+    peak_pvs = None
+    peak_pvs_at = None
+    peak_pvs_location_id = None
+    peak_pvs_location_name = None
+    last_event = None
+    false_trigger_count = 0
+
+    for loc, res in zip(locations, results):
+        st = res.get("stats", {}) or {}
+        ec = st.get("event_count", 0) or 0
+        total_events += ec
+        false_trigger_count += st.get("false_trigger_count", 0) or 0
+
+        ev_last = st.get("last_event")
+        if ev_last and (last_event is None or ev_last > last_event):
+            last_event = ev_last
+
+        ev_peak = st.get("peak_pvs")
+        if ev_peak is not None and (peak_pvs is None or ev_peak > peak_pvs):
+            peak_pvs = ev_peak
+            peak_pvs_at = st.get("peak_pvs_at")
+            peak_pvs_location_id = loc.id
+            peak_pvs_location_name = loc.name
+
+        per_location.append({
+            "location_id":   loc.id,
+            "location_name": loc.name,
+            "event_count":   ec,
+            "peak_pvs":      ev_peak,
+            "last_event":    ev_last,
+        })
+
+    per_location.sort(key=lambda r: r["event_count"], reverse=True)
+
+    return {
+        "project_id":             project_id,
+        "total_events":            total_events,
+        "peak_pvs":                peak_pvs,
+        "peak_pvs_at":             peak_pvs_at,
+        "peak_pvs_location_id":    peak_pvs_location_id,
+        "peak_pvs_location_name":  peak_pvs_location_name,
+        "last_event":              last_event,
+        "false_trigger_count":     false_trigger_count,
+        "per_location":            per_location,
+        "vibration_location_count": len(locations),
+    }
+
+
+# ── Stats helpers ─────────────────────────────────────────────────────────────
+
+
+def _empty_stats() -> dict:
+    return {
+        "event_count":         0,
+        "peak_pvs":            None,
+        "peak_pvs_at":         None,
+        "peak_pvs_serial":     None,
+        "last_event":          None,
+        "false_trigger_count": 0,
+    }
+
+
+def _compute_stats(events: list[dict]) -> dict:
+    """Roll up summary stats from a merged event list.  Cheap O(N) pass."""
+    if not events:
+        return _empty_stats()
+
+    peak_pvs = None
+    peak_pvs_at = None
+    peak_pvs_serial = None
+    last_event = None
+    false_trigger_count = 0
+
+    for ev in events:
+        pvs = ev.get("peak_vector_sum")
+        if pvs is not None and (peak_pvs is None or pvs > peak_pvs):
+            peak_pvs = pvs
+            peak_pvs_at = ev.get("timestamp")
+            peak_pvs_serial = ev.get("serial")
+
+        ts = ev.get("timestamp")
+        if ts and (last_event is None or ts > last_event):
+            last_event = ts
+
+        if ev.get("false_trigger"):
+            false_trigger_count += 1
+
+    return {
+        "event_count":         len(events),
+        "peak_pvs":            peak_pvs,
+        "peak_pvs_at":         peak_pvs_at,
+        "peak_pvs_serial":     peak_pvs_serial,
+        "last_event":          last_event,
+        "false_trigger_count": false_trigger_count,
+    }

templates/partials/projects/vibration_summary.html

@@ -0,0 +1,76 @@
+{# Project-wide vibration events roll-up.  Loaded via HTMX. #}
+{% if summary.vibration_location_count == 0 %}
+<div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-4">
+    <div class="text-sm text-gray-500 dark:text-gray-400">
+        No vibration monitoring locations yet.  Add one to start collecting events.
+    </div>
+</div>
+{% else %}
+<div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-5">
+    <div class="flex items-center justify-between mb-3">
+        <h3 class="text-sm font-semibold text-gray-700 dark:text-gray-300 uppercase tracking-wider">
+            Project-wide vibration events
+        </h3>
+        <span class="text-xs text-gray-500 dark:text-gray-400">
+            across {{ summary.vibration_location_count }} location{{ '' if summary.vibration_location_count == 1 else 's' }}
+        </span>
+    </div>
+
+    <!-- KPI tiles -->
+    <div class="grid grid-cols-2 md:grid-cols-4 gap-3 mb-4">
+        <div class="bg-gray-50 dark:bg-slate-900/50 rounded-lg p-3 flex flex-col">
+            <span class="text-xs text-gray-500 dark:text-gray-400 uppercase tracking-wider">Total Events</span>
+            <span class="text-2xl font-bold text-gray-900 dark:text-white mt-1">{{ "{:,}".format(summary.total_events) }}</span>
+        </div>
+        <div class="bg-gray-50 dark:bg-slate-900/50 rounded-lg p-3 flex flex-col">
+            <span class="text-xs text-gray-500 dark:text-gray-400 uppercase tracking-wider">Peak PVS</span>
+            {% if summary.peak_pvs is not none %}
+            <span class="text-2xl font-bold text-gray-900 dark:text-white mt-1">{{ "%.4f"|format(summary.peak_pvs) }} <span class="text-sm font-normal">in/s</span></span>
+            <a href="/projects/{{ summary.project_id }}/nrl/{{ summary.peak_pvs_location_id }}"
+               class="text-xs text-seismo-orange hover:text-seismo-navy truncate mt-1"
+               title="{{ summary.peak_pvs_location_name }}">
+                {{ summary.peak_pvs_location_name }}
+                {% if summary.peak_pvs_at %} · {{ summary.peak_pvs_at[:10] }}{% endif %}
+            </a>
+            {% else %}
+            <span class="text-2xl font-bold text-gray-900 dark:text-white mt-1">—</span>
+            {% endif %}
+        </div>
+        <div class="bg-gray-50 dark:bg-slate-900/50 rounded-lg p-3 flex flex-col">
+            <span class="text-xs text-gray-500 dark:text-gray-400 uppercase tracking-wider">Last Event</span>
+            {% if summary.last_event %}
+            <span class="text-base font-bold text-gray-900 dark:text-white mt-1">{{ summary.last_event[:19].replace('T', ' ') }}</span>
+            {% else %}
+            <span class="text-2xl font-bold text-gray-900 dark:text-white mt-1">—</span>
+            {% endif %}
+        </div>
+        <div class="bg-gray-50 dark:bg-slate-900/50 rounded-lg p-3 flex flex-col">
+            <span class="text-xs text-gray-500 dark:text-gray-400 uppercase tracking-wider">False Triggers</span>
+            <span class="text-2xl font-bold {% if summary.false_trigger_count > 0 %}text-amber-600 dark:text-amber-400{% else %}text-gray-900 dark:text-white{% endif %} mt-1">{{ "{:,}".format(summary.false_trigger_count) }}</span>
+        </div>
+    </div>
+
+    {% if summary.per_location and summary.total_events > 0 %}
+    <!-- Top locations by activity -->
+    <div>
+        <h4 class="text-xs font-semibold text-gray-500 dark:text-gray-400 uppercase tracking-wider mb-2">Top locations by activity</h4>
+        <div class="space-y-1.5">
+            {% for loc in summary.per_location[:5] %}
+            <a href="/projects/{{ summary.project_id }}/nrl/{{ loc.location_id }}"
+               class="flex items-center justify-between py-1.5 px-3 rounded hover:bg-gray-50 dark:hover:bg-slate-700/50 transition-colors">
+                <span class="text-sm font-medium text-gray-900 dark:text-white truncate">
+                    📍 {{ loc.location_name }}
+                </span>
+                <span class="flex items-center gap-4 text-sm text-gray-600 dark:text-gray-400 whitespace-nowrap ml-3">
+                    <span>{{ "{:,}".format(loc.event_count) }} event{{ '' if loc.event_count == 1 else 's' }}</span>
+                    {% if loc.peak_pvs is not none %}
+                    <span class="text-xs text-gray-500">peak {{ "%.4f"|format(loc.peak_pvs) }}</span>
+                    {% endif %}
+                </span>
+            </a>
+            {% endfor %}
+        </div>
+    </div>
+    {% endif %}
+</div>
+{% endif %}

templates/projects/detail.html

@@ -90,6 +90,17 @@
 
         <!-- Vibration Locations sub-panel -->
         <div id="vib-sub-locations" class="vib-sub-panel">
+            <!-- Project-wide vibration events roll-up -->
+            <div id="vibration-summary"
+                 hx-get="/api/projects/{{ project_id }}/vibration_summary"
+                 hx-trigger="load"
+                 hx-swap="innerHTML"
+                 class="mb-5">
+                <div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-4">
+                    <div class="text-sm text-gray-500 dark:text-gray-400">Loading project summary…</div>
+                </div>
+            </div>
+
             <div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-6">
                 <div class="flex items-center justify-between mb-6">
                     <h2 class="text-xl font-semibold text-gray-900 dark:text-white">Monitoring Locations</h2>

templates/unit_detail.html

@@ -278,30 +278,106 @@
                 <p id="viewNote" class="mt-1 text-gray-900 dark:text-white whitespace-pre-wrap">--</p>
             </div>
 
-            <!-- Deployment History -->
+            <!-- Deployment Timeline (Phase 4 unified view — derived from
+                 unit_assignments + unit_history + SFM event overlay) -->
             <div class="border-t border-gray-200 dark:border-gray-700 pt-6">
                 <div class="flex justify-between items-center mb-4">
-                    <h3 class="text-lg font-semibold text-gray-900 dark:text-white">Deployment History</h3>
-                    <button onclick="openNewDeploymentModal()" class="px-3 py-1.5 bg-seismo-orange hover:bg-orange-600 text-white rounded-lg text-sm transition-colors flex items-center gap-1.5">
-                        <svg class="w-4 h-4" fill="none" stroke="currentColor" viewBox="0 0 24 24">
-                            <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M12 4v16m8-8H4"></path>
-                        </svg>
-                        Log Deployment
+                    <h3 class="text-lg font-semibold text-gray-900 dark:text-white">Deployment Timeline</h3>
+                    <button onclick="loadDeploymentTimeline()" class="px-3 py-1.5 text-sm rounded-lg border border-gray-300 dark:border-gray-600 hover:bg-gray-50 dark:hover:bg-gray-700 text-gray-700 dark:text-gray-300">
+                        ↻ Refresh
                     </button>
                 </div>
-                <div id="deploymentHistory" class="space-y-3">
-                    <p class="text-sm text-gray-500 dark:text-gray-400">Loading...</p>
+                <div id="deploymentTimeline" class="space-y-3">
+                    <p class="text-sm text-gray-500 dark:text-gray-400">Loading timeline…</p>
                 </div>
             </div>
 
-            <!-- Unit History Timeline -->
-            <div class="border-t border-gray-200 dark:border-gray-700 pt-6">
-                <h3 class="text-lg font-semibold text-gray-900 dark:text-white mb-4">Timeline</h3>
-                <div id="historyTimeline" class="space-y-3">
-                    <p class="text-sm text-gray-500 dark:text-gray-400">Loading history...</p>
+            <!-- SFM Events (seismographs only) -->
+            <div id="sfmEventsSection" class="border-t border-gray-200 dark:border-gray-700 pt-6 hidden">
+                <div class="flex justify-between items-center mb-4">
+                    <h3 class="text-lg font-semibold text-gray-900 dark:text-white">SFM Events</h3>
+                    <button onclick="loadUnitEvents()" class="px-3 py-1.5 text-sm rounded-lg border border-gray-300 dark:border-gray-600 hover:bg-gray-50 dark:hover:bg-gray-700 text-gray-700 dark:text-gray-300">
+                        ↻ Refresh
+                    </button>
+                </div>
+
+                <!-- KPI tiles -->
+                <div class="grid grid-cols-2 md:grid-cols-4 gap-3 mb-4">
+                    <div class="bg-gray-50 dark:bg-slate-900/50 rounded-lg p-3 flex flex-col">
+                        <span class="text-xs text-gray-500 dark:text-gray-400 uppercase tracking-wider">Total Events</span>
+                        <span id="ue-stat-total" class="text-2xl font-bold text-gray-900 dark:text-white mt-1">—</span>
+                    </div>
+                    <div class="bg-gray-50 dark:bg-slate-900/50 rounded-lg p-3 flex flex-col">
+                        <span class="text-xs text-gray-500 dark:text-gray-400 uppercase tracking-wider">Unattributed</span>
+                        <span id="ue-stat-unattr" class="text-2xl font-bold text-gray-900 dark:text-white mt-1">—</span>
+                        <span class="text-xs text-gray-500 dark:text-gray-400 mt-1">outside any assignment window</span>
+                    </div>
+                    <div class="bg-gray-50 dark:bg-slate-900/50 rounded-lg p-3 flex flex-col">
+                        <span class="text-xs text-gray-500 dark:text-gray-400 uppercase tracking-wider">Peak PVS</span>
+                        <span id="ue-stat-peak" class="text-2xl font-bold text-gray-900 dark:text-white mt-1">—</span>
+                        <span id="ue-stat-peak-when" class="text-xs text-gray-500 dark:text-gray-400 mt-1">—</span>
+                    </div>
+                    <div class="bg-gray-50 dark:bg-slate-900/50 rounded-lg p-3 flex flex-col">
+                        <span class="text-xs text-gray-500 dark:text-gray-400 uppercase tracking-wider">Last Event</span>
+                        <span id="ue-stat-last" class="text-base font-bold text-gray-900 dark:text-white mt-1">—</span>
+                    </div>
+                </div>
+
+                <!-- Filters -->
+                <div class="flex flex-wrap items-end gap-3 mb-4">
+                    <div class="flex flex-col gap-1">
+                        <label class="text-xs text-gray-500 dark:text-gray-400">Bucket</label>
+                        <select id="ue-filter-bucket" onchange="loadUnitEvents()"
+                                class="px-3 py-1.5 text-sm border border-gray-300 dark:border-gray-600 rounded-lg bg-white dark:bg-slate-700 text-gray-900 dark:text-white">
+                            <option value="all">All Events</option>
+                            <option value="attributed">Attributed Only</option>
+                            <option value="unattributed">Unattributed Only</option>
+                        </select>
+                    </div>
+                    <div class="flex flex-col gap-1">
+                        <label class="text-xs text-gray-500 dark:text-gray-400">From</label>
+                        <input type="datetime-local" id="ue-filter-from" onchange="loadUnitEvents()"
+                               class="px-3 py-1.5 text-sm border border-gray-300 dark:border-gray-600 rounded-lg bg-white dark:bg-slate-700 text-gray-900 dark:text-white">
+                    </div>
+                    <div class="flex flex-col gap-1">
+                        <label class="text-xs text-gray-500 dark:text-gray-400">To</label>
+                        <input type="datetime-local" id="ue-filter-to" onchange="loadUnitEvents()"
+                               class="px-3 py-1.5 text-sm border border-gray-300 dark:border-gray-600 rounded-lg bg-white dark:bg-slate-700 text-gray-900 dark:text-white">
+                    </div>
+                    <div class="flex flex-col gap-1">
+                        <label class="text-xs text-gray-500 dark:text-gray-400">False Triggers</label>
+                        <select id="ue-filter-ft" onchange="loadUnitEvents()"
+                                class="px-3 py-1.5 text-sm border border-gray-300 dark:border-gray-600 rounded-lg bg-white dark:bg-slate-700 text-gray-900 dark:text-white">
+                            <option value="">All</option>
+                            <option value="false">Real Only</option>
+                            <option value="true">FT Only</option>
+                        </select>
+                    </div>
+                    <div class="flex flex-col gap-1">
+                        <label class="text-xs text-gray-500 dark:text-gray-400">Limit</label>
+                        <select id="ue-filter-limit" onchange="loadUnitEvents()"
+                                class="px-3 py-1.5 text-sm border border-gray-300 dark:border-gray-600 rounded-lg bg-white dark:bg-slate-700 text-gray-900 dark:text-white">
+                            <option value="100">100</option>
+                            <option value="250">250</option>
+                            <option value="500" selected>500</option>
+                            <option value="1000">1000</option>
+                        </select>
+                    </div>
+                    <button onclick="clearUnitEventFilters()"
+                            class="px-3 py-1.5 text-sm text-gray-600 dark:text-gray-400 hover:text-gray-900 dark:hover:text-white">
+                        Clear
+                    </button>
+                </div>
+
+                <!-- Event table -->
+                <div id="ue-events-container" class="overflow-x-auto rounded-lg border border-gray-200 dark:border-gray-700">
+                    <div class="text-center py-12 text-gray-500 dark:text-gray-400 text-sm">
+                        Loading events…
+                    </div>
                 </div>
             </div>
 
+
             <!-- Photos -->
             <div class="border-t border-gray-200 dark:border-gray-700 pt-6">
                 <div class="flex justify-between items-start mb-4">
@@ -1547,8 +1623,15 @@ async function uploadPhoto(file) {
     }
 }
 
-// Load and display unit history timeline
+// Legacy timeline loader — Phase 4 unified the timeline view.  Now a shim
+// that delegates to loadDeploymentTimeline() so existing callers from modal
+// save handlers still trigger a refresh of the visible section.
 async function loadUnitHistory() {
+    if (typeof loadDeploymentTimeline === 'function') {
+        return loadDeploymentTimeline();
+    }
+}
+async function _legacy_loadUnitHistory_unused() {
     try {
         const response = await fetch(`/api/roster/history/${unitId}`);
         if (!response.ok) {
@@ -1720,10 +1803,18 @@ async function pingModem() {
 }
 
 // ============================================================
-// Deployment History
+// Deployment History (legacy — Phase 4 superseded by deployment_timeline)
 // ============================================================
 
+// Phase 4 shim: delegate to the unified timeline loader so existing modal
+// save handlers (legacy "Log Deployment" form, edit-save callbacks) still
+// trigger a refresh of the visible Deployment Timeline section.
 async function loadDeploymentHistory() {
+    if (typeof loadDeploymentTimeline === 'function') {
+        return loadDeploymentTimeline();
+    }
+}
+async function _legacy_loadDeploymentHistory_unused() {
     try {
         const res = await fetch(`/api/deployments/${unitId}`);
         const data = await res.json();
@@ -1884,10 +1975,337 @@ loadCalibrationInterval();
 setupCalibrationAutoCalc();
 loadUnitData().then(() => {
     loadPhotos();
-    loadUnitHistory();
-    loadDeploymentHistory();
+    loadDeploymentTimeline();
+    if (currentUnit && currentUnit.device_type === 'seismograph') {
+        document.getElementById('sfmEventsSection').classList.remove('hidden');
+        loadUnitEvents();
+    }
 });
 
+// ── Unified Deployment Timeline (Phase 4) ────────────────────────────────────
+// Replaces the legacy loadDeploymentHistory() + loadUnitHistory() pair.
+// Derives entries from unit_assignments + unit_history + SFM event overlay.
+
+async function loadDeploymentTimeline() {
+    const container = document.getElementById('deploymentTimeline');
+    container.innerHTML = '<p class="text-sm text-gray-500 dark:text-gray-400">Loading timeline…</p>';
+
+    try {
+        const r = await fetch(`/api/units/${currentUnit.id}/deployment_timeline`);
+        if (!r.ok) throw new Error('HTTP ' + r.status);
+        const d = await r.json();
+        renderDeploymentTimeline(d.entries || [], container);
+    } catch (e) {
+        container.innerHTML = `<p class="text-sm text-red-500">Failed to load timeline: ${e.message}</p>`;
+    }
+}
+
+function _dtFmtDate(iso) {
+    if (!iso) return '—';
+    return iso.slice(0, 10);
+}
+
+function _dtFmtDateTime(iso) {
+    if (!iso) return '—';
+    return iso.slice(0, 19).replace('T', ' ');
+}
+
+function _dtEsc(s) {
+    if (s == null) return '';
+    return String(s).replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/"/g, '&quot;');
+}
+
+function _dtPpvClass(v) {
+    if (v == null) return 'text-gray-400';
+    if (v < 0.5) return 'text-green-600 dark:text-green-400';
+    if (v < 2.0) return 'text-amber-600 dark:text-amber-400';
+    return 'text-red-600 dark:text-red-400 font-semibold';
+}
+
+function _dtRenderAssignment(e) {
+    const start = _dtFmtDate(e.starts_at);
+    const end   = e.is_active ? 'present' : _dtFmtDate(e.ends_at);
+    const dur   = (e.duration_days != null)
+        ? `<span class="text-xs text-gray-500 dark:text-gray-400 ml-2">(${e.duration_days.toFixed(1)} day${e.duration_days === 1 ? '' : 's'})</span>`
+        : '';
+    const ov = e.event_overlay || {};
+    const evCount = ov.event_count ?? 0;
+    const peak    = ov.peak_pvs;
+
+    const locLink = e.location_id
+        ? `<a href="/projects/${_dtEsc(e.project_id)}/nrl/${_dtEsc(e.location_id)}" class="text-seismo-orange hover:text-seismo-navy font-medium">📍 ${_dtEsc(e.location_name || 'unnamed location')}</a>`
+        : `<span class="text-gray-500 dark:text-gray-400 italic">📍 (no location FK — synthesized from legacy deployment_records)</span>`;
+
+    const projLine = e.project_name
+        ? `<div class="text-xs text-gray-500 dark:text-gray-400 mt-0.5">${_dtEsc(e.project_name)}</div>`
+        : '';
+
+    const activeBadge = e.is_active
+        ? '<span class="px-2 py-0.5 rounded text-xs bg-green-100 text-green-800 dark:bg-green-900/30 dark:text-green-300">active</span>'
+        : '';
+
+    const overlay = evCount > 0
+        ? `<div class="mt-2 flex items-center gap-4 text-xs text-gray-600 dark:text-gray-400">
+               <span><strong class="text-gray-900 dark:text-white">${evCount.toLocaleString()}</strong> event${evCount === 1 ? '' : 's'}</span>
+               ${peak != null ? `<span>peak <strong class="${_dtPpvClass(peak)}">${peak.toFixed(4)} in/s</strong></span>` : ''}
+               ${ov.last_event ? `<span>last ${_dtFmtDateTime(ov.last_event)}</span>` : ''}
+           </div>`
+        : `<div class="mt-2 text-xs text-gray-500 dark:text-gray-400 italic">No events recorded during this window.</div>`;
+
+    const notes = e.notes
+        ? `<div class="mt-2 text-xs text-gray-600 dark:text-gray-400 italic">${_dtEsc(e.notes)}</div>`
+        : '';
+
+    return `<div class="flex gap-3">
+        <div class="flex flex-col items-center pt-1">
+            <span class="w-3 h-3 rounded-full ${e.is_active ? 'bg-green-500' : 'bg-seismo-orange'}"></span>
+        </div>
+        <div class="flex-1 bg-gray-50 dark:bg-slate-900/40 rounded-lg p-3">
+            <div class="flex items-center justify-between flex-wrap gap-2">
+                <div class="text-sm text-gray-700 dark:text-gray-300">
+                    <strong>${start}</strong> → <strong>${end}</strong>${dur}
+                </div>
+                ${activeBadge}
+            </div>
+            <div class="mt-1">${locLink}</div>
+            ${projLine}
+            ${overlay}
+            ${notes}
+        </div>
+    </div>`;
+}
+
+function _dtRenderGap(e) {
+    return `<div class="flex gap-3">
+        <div class="flex flex-col items-center pt-1">
+            <span class="w-3 h-3 rounded-full border-2 border-gray-400 dark:border-gray-500"></span>
+        </div>
+        <div class="flex-1 bg-gray-50/40 dark:bg-slate-900/20 rounded-lg p-3 border border-dashed border-gray-300 dark:border-gray-700">
+            <div class="text-sm text-gray-600 dark:text-gray-400">
+                <strong>${_dtFmtDate(e.starts_at)}</strong> → <strong>${_dtFmtDate(e.ends_at)}</strong>
+                <span class="text-xs ml-2">(${e.duration_days.toFixed(1)} day${e.duration_days === 1 ? '' : 's'} idle)</span>
+            </div>
+            <div class="text-xs text-gray-500 dark:text-gray-400 mt-0.5">No active assignment</div>
+        </div>
+    </div>`;
+}
+
+function _dtRenderStateChange(e) {
+    // Friendly labels for known change_types.
+    const labels = {
+        deployed_change:           'Deployed status changed',
+        retired_change:            'Retired status changed',
+        calibration_status_change: 'Calibration status changed',
+        last_calibrated_change:    'Last calibrated updated',
+        next_calibration_due_change: 'Next calibration due updated',
+        allocation_change:         'Allocation changed',
+    };
+    const label = labels[e.change_type] || e.change_type;
+
+    return `<div class="flex gap-3">
+        <div class="flex flex-col items-center pt-1">
+            <span class="w-3 h-3 rounded-full bg-seismo-navy"></span>
+        </div>
+        <div class="flex-1 bg-gray-50 dark:bg-slate-900/30 rounded-lg p-3">
+            <div class="text-sm text-gray-700 dark:text-gray-300">
+                📅 <strong>${_dtFmtDateTime(e.starts_at)}</strong> — ${_dtEsc(label)}
+            </div>
+            <div class="text-xs text-gray-500 dark:text-gray-400 mt-0.5">
+                ${_dtEsc(e.old_value || '—')} → <strong>${_dtEsc(e.new_value || '—')}</strong>
+            </div>
+            ${e.history_notes ? `<div class="text-xs text-gray-500 dark:text-gray-400 mt-1 italic">${_dtEsc(e.history_notes)}</div>` : ''}
+        </div>
+    </div>`;
+}
+
+function renderDeploymentTimeline(entries, container) {
+    if (!entries.length) {
+        container.innerHTML = '<p class="text-sm text-gray-500 dark:text-gray-400">No deployment history yet. Assign this unit to a project location to start a deployment record.</p>';
+        return;
+    }
+    const html = entries.map(e => {
+        if (e.kind === 'assignment')   return _dtRenderAssignment(e);
+        if (e.kind === 'gap')          return _dtRenderGap(e);
+        if (e.kind === 'state_change') return _dtRenderStateChange(e);
+        return '';
+    }).join('');
+    container.innerHTML = html;
+}
+
+// ── SFM Events section ──────────────────────────────────────────────────────
+function clearUnitEventFilters() {
+    document.getElementById('ue-filter-bucket').value = 'all';
+    document.getElementById('ue-filter-from').value = '';
+    document.getElementById('ue-filter-to').value = '';
+    document.getElementById('ue-filter-ft').value = '';
+    document.getElementById('ue-filter-limit').value = '500';
+    loadUnitEvents();
+}
+
+async function loadUnitEvents() {
+    if (!currentUnit || currentUnit.device_type !== 'seismograph') return;
+    const container = document.getElementById('ue-events-container');
+    container.innerHTML = '<div class="text-center py-12 text-gray-500 dark:text-gray-400 text-sm">Loading events…</div>';
+
+    const params = new URLSearchParams();
+    const bucket = document.getElementById('ue-filter-bucket').value;
+    const from   = document.getElementById('ue-filter-from').value;
+    const to     = document.getElementById('ue-filter-to').value;
+    const ft     = document.getElementById('ue-filter-ft').value;
+    const limit  = document.getElementById('ue-filter-limit').value;
+    params.set('bucket', bucket);
+    if (from)  params.set('from_dt', from.replace('T', ' '));
+    if (to)    params.set('to_dt',   to.replace('T', ' '));
+    if (ft)    params.set('false_trigger', ft);
+    params.set('limit', limit);
+
+    try {
+        const r = await fetch(`/api/units/${currentUnit.id}/events?${params.toString()}`);
+        if (!r.ok) {
+            const err = await r.json().catch(() => ({detail: 'HTTP ' + r.status}));
+            throw new Error(err.detail || 'HTTP ' + r.status);
+        }
+        const d = await r.json();
+        renderUnitEventStats(d.stats);
+        renderUnitEventTable(d.events, d.count, container, bucket, d.assignments_total);
+    } catch (e) {
+        container.innerHTML = `<div class="text-center py-12 text-red-500 text-sm">Failed to load events: ${e.message}</div>`;
+    }
+}
+
+function renderUnitEventStats(stats) {
+    const s = stats || {};
+    document.getElementById('ue-stat-total').textContent  = (s.event_count ?? 0).toLocaleString();
+    const unattrEl = document.getElementById('ue-stat-unattr');
+    unattrEl.textContent = (s.unattributed_count ?? 0).toLocaleString();
+    // Highlight unattributed in amber/red if non-zero — visual signal that
+    // the operator has assignment-window cleanup to do.
+    unattrEl.className = 'text-2xl font-bold mt-1 ' + (
+        (s.unattributed_count ?? 0) > 0
+            ? 'text-amber-600 dark:text-amber-400'
+            : 'text-gray-900 dark:text-white'
+    );
+
+    if (s.peak_pvs != null) {
+        document.getElementById('ue-stat-peak').textContent = s.peak_pvs.toFixed(4) + ' in/s';
+        const when = s.peak_pvs_at ? s.peak_pvs_at.slice(0, 10) : '';
+        document.getElementById('ue-stat-peak-when').textContent = when || '—';
+    } else {
+        document.getElementById('ue-stat-peak').textContent = '—';
+        document.getElementById('ue-stat-peak-when').textContent = '—';
+    }
+
+    if (s.last_event) {
+        const dt = s.last_event.slice(0, 19).replace('T', ' ');
+        document.getElementById('ue-stat-last').textContent = dt;
+    } else {
+        document.getElementById('ue-stat-last').textContent = '—';
+    }
+}
+
+function _ueFmtPPV(v) {
+    if (v == null) return '—';
+    return v.toFixed(4);
+}
+
+function _uePpvClass(v) {
+    if (v == null) return 'text-gray-400';
+    if (v < 0.5) return 'text-green-600 dark:text-green-400';
+    if (v < 2.0) return 'text-amber-600 dark:text-amber-400';
+    return 'text-red-600 dark:text-red-400 font-semibold';
+}
+
+function _ueEsc(s) {
+    if (s == null) return '';
+    return String(s).replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/"/g, '&quot;');
+}
+
+function _ueAttrCell(ev) {
+    const a = ev.attribution;
+    if (a) {
+        // Attributed: project / location link.
+        const projLabel = _ueEsc(a.project_name || '—');
+        const locLabel  = _ueEsc(a.location_name || '—');
+        return `<a href="/projects/${_ueEsc(a.project_id)}/nrl/${_ueEsc(a.location_id)}"
+                   class="text-seismo-orange hover:text-seismo-navy"
+                   title="${projLabel} → ${locLabel}">
+                    📍 ${locLabel}
+                </a>
+                <div class="text-xs text-gray-500 dark:text-gray-400">${projLabel}</div>`;
+    }
+    // Unattributed: show nearest assignment + delta for context.
+    const n = ev.nearest_assignment;
+    if (n) {
+        const sign = n.delta_days < 0 ? 'before' : (n.delta_days > 0 ? 'after' : 'within boundary');
+        const days = Math.abs(n.delta_days);
+        const daysLabel = days < 1
+            ? `<${(days * 24).toFixed(1)}h`
+            : `${days.toFixed(1)}d`;
+        return `<span class="px-2 py-0.5 rounded text-xs bg-amber-100 text-amber-800 dark:bg-amber-900/30 dark:text-amber-300">⚠ Unattributed</span>
+                <div class="text-xs text-gray-500 dark:text-gray-400 mt-0.5">
+                    ${daysLabel} ${_ueEsc(sign)} <a href="/projects/${_ueEsc(n.project_id)}/nrl/${_ueEsc(n.location_id)}" class="text-seismo-orange hover:text-seismo-navy">${_ueEsc(n.location_name || '?')}</a>
+                </div>`;
+    }
+    return `<span class="px-2 py-0.5 rounded text-xs bg-gray-200 text-gray-700 dark:bg-gray-700 dark:text-gray-300">⚠ No assignments</span>`;
+}
+
+function renderUnitEventTable(events, total, container, bucket, assignmentsTotal) {
+    if (!events || events.length === 0) {
+        let msg;
+        if (bucket === 'unattributed') {
+            msg = assignmentsTotal === 0
+                ? 'No assignments yet — every event from this unit is unattributed. Assign it to a project location to start attributing events.'
+                : '✅ All events for this unit are attributed to a project/location.';
+        } else if (bucket === 'attributed') {
+            msg = assignmentsTotal === 0
+                ? 'No assignments yet for this unit.'
+                : 'No events recorded inside any assignment window with the current filter.';
+        } else {
+            msg = 'No events found for this unit with the current filter.';
+        }
+        container.innerHTML = `<div class="text-center py-12 text-gray-500 dark:text-gray-400 text-sm">${msg}</div>`;
+        return;
+    }
+
+    const rows = events.map(ev => {
+        const ts = ev.timestamp ? ev.timestamp.replace('T', ' ').slice(0, 19) : '—';
+        const tran = _ueFmtPPV(ev.tran_ppv);
+        const vert = _ueFmtPPV(ev.vert_ppv);
+        const lng  = _ueFmtPPV(ev.long_ppv);
+        const pvs  = _ueFmtPPV(ev.peak_vector_sum);
+        const ft   = ev.false_trigger
+            ? '<span class="px-2 py-0.5 rounded text-xs bg-yellow-100 text-yellow-800 dark:bg-yellow-900/30 dark:text-yellow-300">FT</span>'
+            : '';
+
+        return `<tr class="hover:bg-gray-50 dark:hover:bg-slate-700/50 ${ev.attribution ? '' : 'bg-amber-50/40 dark:bg-amber-900/10'}">
+            <td class="px-4 py-2.5 text-sm text-gray-900 dark:text-white whitespace-nowrap">${ts}</td>
+            <td class="px-4 py-2.5 text-sm font-mono ${_uePpvClass(ev.tran_ppv)}">${tran}</td>
+            <td class="px-4 py-2.5 text-sm font-mono ${_uePpvClass(ev.vert_ppv)}">${vert}</td>
+            <td class="px-4 py-2.5 text-sm font-mono ${_uePpvClass(ev.long_ppv)}">${lng}</td>
+            <td class="px-4 py-2.5 text-sm font-mono font-semibold ${_uePpvClass(ev.peak_vector_sum)}">${pvs}</td>
+            <td class="px-4 py-2.5 text-sm">${ft}</td>
+            <td class="px-4 py-2.5 text-sm">${_ueAttrCell(ev)}</td>
+        </tr>`;
+    }).join('');
+
+    container.innerHTML = `
+        <div class="text-xs text-gray-500 dark:text-gray-400 px-4 pt-3 pb-1">Showing ${events.length} of ${total.toLocaleString()} event${total === 1 ? '' : 's'}</div>
+        <table class="w-full text-left">
+            <thead class="bg-gray-50 dark:bg-slate-700 border-b border-gray-200 dark:border-gray-600">
+                <tr>
+                    <th class="px-4 py-3 text-xs font-medium text-gray-700 dark:text-gray-300 uppercase tracking-wider">Timestamp</th>
+                    <th class="px-4 py-3 text-xs font-medium text-gray-700 dark:text-gray-300 uppercase tracking-wider">Tran</th>
+                    <th class="px-4 py-3 text-xs font-medium text-gray-700 dark:text-gray-300 uppercase tracking-wider">Vert</th>
+                    <th class="px-4 py-3 text-xs font-medium text-gray-700 dark:text-gray-300 uppercase tracking-wider">Long</th>
+                    <th class="px-4 py-3 text-xs font-medium text-gray-700 dark:text-gray-300 uppercase tracking-wider">PVS</th>
+                    <th class="px-4 py-3 text-xs font-medium text-gray-700 dark:text-gray-300 uppercase tracking-wider">Flags</th>
+                    <th class="px-4 py-3 text-xs font-medium text-gray-700 dark:text-gray-300 uppercase tracking-wider">Attribution</th>
+                </tr>
+            </thead>
+            <tbody class="divide-y divide-gray-200 dark:divide-gray-700">${rows}</tbody>
+        </table>`;
+}
+
 // ===== Pair Device Modal Functions =====
 let pairModalModems = []; // Cache loaded modems
 let pairModalDeviceType = ''; // Current device type

templates/vibration_location_detail.html

@@ -65,6 +65,11 @@
                 class="tab-button px-4 py-3 border-b-2 font-medium text-sm transition-colors border-seismo-orange text-seismo-orange">
             Overview
         </button>
+        <button onclick="switchTab('events')"
+                data-tab="events"
+                class="tab-button px-4 py-3 border-b-2 border-transparent font-medium text-sm text-gray-600 dark:text-gray-400 hover:text-gray-900 dark:hover:text-white hover:border-gray-300 dark:hover:border-gray-600 transition-colors">
+            Events
+        </button>
         <button onclick="switchTab('settings')"
                 data-tab="settings"
                 class="tab-button px-4 py-3 border-b-2 border-transparent font-medium text-sm text-gray-600 dark:text-gray-400 hover:text-gray-900 dark:hover:text-white hover:border-gray-300 dark:hover:border-gray-600 transition-colors">
@@ -185,6 +190,152 @@
         </div>
     </div>
 
+    <!-- Events Tab -->
+    <div id="events-tab" class="tab-panel hidden">
+        <!-- Summary stats -->
+        <div id="events-stats" class="grid grid-cols-2 md:grid-cols-4 gap-4 mb-6">
+            <div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-4 flex flex-col">
+                <span class="text-xs text-gray-500 dark:text-gray-400 uppercase tracking-wider">Total Events</span>
+                <span id="ev-stat-count" class="text-3xl font-bold text-gray-900 dark:text-white mt-1">—</span>
+            </div>
+            <div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-4 flex flex-col">
+                <span class="text-xs text-gray-500 dark:text-gray-400 uppercase tracking-wider">Peak PVS</span>
+                <span id="ev-stat-peak" class="text-3xl font-bold text-gray-900 dark:text-white mt-1">—</span>
+                <span id="ev-stat-peak-when" class="text-xs text-gray-500 dark:text-gray-400 mt-1">—</span>
+            </div>
+            <div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-4 flex flex-col">
+                <span class="text-xs text-gray-500 dark:text-gray-400 uppercase tracking-wider">Last Event</span>
+                <span id="ev-stat-last" class="text-lg font-bold text-gray-900 dark:text-white mt-1">—</span>
+            </div>
+            <div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-4 flex flex-col">
+                <span class="text-xs text-gray-500 dark:text-gray-400 uppercase tracking-wider">False Triggers</span>
+                <span id="ev-stat-ft" class="text-3xl font-bold text-gray-900 dark:text-white mt-1">—</span>
+            </div>
+        </div>
+
+        <!-- Assignments used (transparency: which seismographs contributed events) -->
+        <div id="events-assignments-card" class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-4 mb-6 hidden">
+            <div class="flex items-center justify-between mb-2">
+                <h3 class="text-sm font-semibold text-gray-700 dark:text-gray-300 uppercase tracking-wider">Seismographs deployed at this location</h3>
+                <span id="ev-assignments-count" class="text-xs text-gray-500 dark:text-gray-400"></span>
+            </div>
+            <div id="ev-assignments-list" class="divide-y divide-gray-200 dark:divide-gray-700"></div>
+            <p class="text-xs text-gray-500 dark:text-gray-400 mt-3">
+                <span class="inline-block w-4 text-center">✎</span>
+                Click the pencil to backdate a deployment so historical events get attributed to this location.
+            </p>
+        </div>
+
+        <!-- Edit-assignment modal -->
+        <div id="assignment-edit-modal" class="hidden fixed inset-0 bg-black bg-opacity-50 z-50 flex items-center justify-center">
+            <div class="bg-white dark:bg-slate-800 rounded-xl shadow-2xl w-full max-w-md m-4">
+                <div class="p-6 border-b border-gray-200 dark:border-gray-700 flex items-center justify-between">
+                    <div>
+                        <h2 class="text-xl font-bold text-gray-900 dark:text-white">Edit Deployment Window</h2>
+                        <p class="text-sm text-gray-500 dark:text-gray-400 mt-1">
+                            <span id="ae-unit-label" class="font-mono text-seismo-orange">—</span>
+                        </p>
+                    </div>
+                    <button onclick="closeAssignmentEditModal()" class="text-gray-500 hover:text-gray-700 dark:text-gray-400">
+                        <svg class="w-6 h-6" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                            <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M6 18L18 6M6 6l12 12"></path>
+                        </svg>
+                    </button>
+                </div>
+                <form id="assignment-edit-form" class="p-6 space-y-4">
+                    <input type="hidden" id="ae-assignment-id">
+
+                    <div>
+                        <label class="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-2">Assigned From</label>
+                        <input type="datetime-local" id="ae-assigned-at" required
+                               class="w-full px-3 py-2 border border-gray-300 dark:border-gray-600 rounded-lg bg-white dark:bg-gray-700 text-gray-900 dark:text-white">
+                    </div>
+
+                    <div>
+                        <label class="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-2">
+                            Assigned Until
+                            <span class="text-xs text-gray-500 ml-1">(leave blank if still active)</span>
+                        </label>
+                        <input type="datetime-local" id="ae-assigned-until"
+                               class="w-full px-3 py-2 border border-gray-300 dark:border-gray-600 rounded-lg bg-white dark:bg-gray-700 text-gray-900 dark:text-white">
+                    </div>
+
+                    <div>
+                        <label class="block text-sm font-medium text-gray-700 dark:text-gray-300 mb-2">Notes</label>
+                        <textarea id="ae-notes" rows="2" placeholder="Optional — e.g. 'backdated to reflect physical install date'"
+                                  class="w-full px-3 py-2 border border-gray-300 dark:border-gray-600 rounded-lg bg-white dark:bg-gray-700 text-gray-900 dark:text-white"></textarea>
+                    </div>
+
+                    <div id="ae-error" class="hidden text-sm text-red-600"></div>
+
+                    <div class="flex justify-end gap-3 pt-2">
+                        <button type="button" onclick="closeAssignmentEditModal()"
+                                class="px-4 py-2 border border-gray-300 dark:border-gray-600 rounded-lg text-gray-700 dark:text-gray-300 hover:bg-gray-50 dark:hover:bg-gray-700">
+                            Cancel
+                        </button>
+                        <button type="submit" id="ae-submit-btn"
+                                class="px-4 py-2 bg-seismo-orange hover:bg-seismo-navy text-white rounded-lg font-medium">
+                            Save
+                        </button>
+                    </div>
+                </form>
+            </div>
+        </div>
+
+        <!-- Filters -->
+        <div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-4 mb-6">
+            <div class="flex flex-wrap items-end gap-3">
+                <div class="flex flex-col gap-1">
+                    <label class="text-xs text-gray-500 dark:text-gray-400">From</label>
+                    <input type="datetime-local" id="ev-filter-from" onchange="loadLocationEvents()"
+                           class="px-3 py-1.5 text-sm border border-gray-300 dark:border-gray-600 rounded-lg bg-white dark:bg-slate-700 text-gray-900 dark:text-white">
+                </div>
+                <div class="flex flex-col gap-1">
+                    <label class="text-xs text-gray-500 dark:text-gray-400">To</label>
+                    <input type="datetime-local" id="ev-filter-to" onchange="loadLocationEvents()"
+                           class="px-3 py-1.5 text-sm border border-gray-300 dark:border-gray-600 rounded-lg bg-white dark:bg-slate-700 text-gray-900 dark:text-white">
+                </div>
+                <div class="flex flex-col gap-1">
+                    <label class="text-xs text-gray-500 dark:text-gray-400">False Triggers</label>
+                    <select id="ev-filter-ft" onchange="loadLocationEvents()"
+                            class="px-3 py-1.5 text-sm border border-gray-300 dark:border-gray-600 rounded-lg bg-white dark:bg-slate-700 text-gray-900 dark:text-white">
+                        <option value="">All Events</option>
+                        <option value="false">Real Events Only</option>
+                        <option value="true">False Triggers Only</option>
+                    </select>
+                </div>
+                <div class="flex flex-col gap-1">
+                    <label class="text-xs text-gray-500 dark:text-gray-400">Limit</label>
+                    <select id="ev-filter-limit" onchange="loadLocationEvents()"
+                            class="px-3 py-1.5 text-sm border border-gray-300 dark:border-gray-600 rounded-lg bg-white dark:bg-slate-700 text-gray-900 dark:text-white">
+                        <option value="100">100</option>
+                        <option value="250">250</option>
+                        <option value="500" selected>500</option>
+                        <option value="1000">1000</option>
+                    </select>
+                </div>
+                <button onclick="clearEventFilters()"
+                        class="px-3 py-1.5 text-sm text-gray-600 dark:text-gray-400 hover:text-gray-900 dark:hover:text-white">
+                    Clear
+                </button>
+                <button onclick="loadLocationEvents()"
+                        class="ml-auto px-4 py-1.5 text-sm bg-seismo-orange text-white rounded-lg hover:bg-seismo-navy">
+                    ↻ Refresh
+                </button>
+            </div>
+        </div>
+
+        <!-- Event table -->
+        <div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg overflow-hidden">
+            <div id="events-container" class="overflow-x-auto">
+                <div class="text-center py-12 text-gray-500 dark:text-gray-400">
+                    <div class="animate-spin rounded-full h-8 w-8 border-b-2 border-seismo-orange mx-auto mb-3"></div>
+                    Loading events…
+                </div>
+            </div>
+        </div>
+    </div>
+
     <!-- Settings Tab -->
     <div id="settings-tab" class="tab-panel hidden">
         <div class="bg-white dark:bg-slate-800 rounded-xl shadow-lg p-6">
@@ -324,6 +475,258 @@ function switchTab(tabName) {
         button.classList.remove('border-transparent', 'text-gray-600', 'dark:text-gray-400');
         button.classList.add('border-seismo-orange', 'text-seismo-orange');
     }
+    // Lazy-load Events tab on first visit (or whenever it's reopened).
+    if (tabName === 'events' && !_eventsLoaded) {
+        loadLocationEvents();
+    }
+}
+
+// ── Events tab ───────────────────────────────────────────────────────────────
+let _eventsLoaded = false;
+
+function clearEventFilters() {
+    document.getElementById('ev-filter-from').value = '';
+    document.getElementById('ev-filter-to').value = '';
+    document.getElementById('ev-filter-ft').value = '';
+    document.getElementById('ev-filter-limit').value = '500';
+    loadLocationEvents();
+}
+
+async function loadLocationEvents() {
+    const container = document.getElementById('events-container');
+    container.innerHTML = '<div class="text-center py-12 text-gray-500 dark:text-gray-400"><div class="animate-spin rounded-full h-8 w-8 border-b-2 border-seismo-orange mx-auto mb-3"></div>Loading events…</div>';
+
+    const params = new URLSearchParams();
+    const from   = document.getElementById('ev-filter-from').value;
+    const to     = document.getElementById('ev-filter-to').value;
+    const ft     = document.getElementById('ev-filter-ft').value;
+    const limit  = document.getElementById('ev-filter-limit').value;
+    if (from)  params.set('from_dt', from.replace('T', ' '));
+    if (to)    params.set('to_dt',   to.replace('T', ' '));
+    if (ft)    params.set('false_trigger', ft);
+    params.set('limit', limit);
+
+    try {
+        const r = await fetch(`/api/projects/${projectId}/locations/${locationId}/events?${params.toString()}`);
+        if (!r.ok) {
+            const err = await r.json().catch(() => ({detail: 'HTTP ' + r.status}));
+            throw new Error(err.detail || 'HTTP ' + r.status);
+        }
+        const d = await r.json();
+        _eventsLoaded = true;
+        renderEventStats(d.stats);
+        renderAssignmentsUsed(d.assignments_used);
+        renderEventTable(d.events, d.count, container);
+    } catch (e) {
+        container.innerHTML = `<div class="text-center py-12 text-red-500 text-sm">Failed to load events: ${e.message}</div>`;
+    }
+}
+
+function renderEventStats(stats) {
+    const s = stats || {};
+    document.getElementById('ev-stat-count').textContent = (s.event_count ?? 0).toLocaleString();
+    document.getElementById('ev-stat-ft').textContent    = (s.false_trigger_count ?? 0).toLocaleString();
+
+    if (s.peak_pvs != null) {
+        document.getElementById('ev-stat-peak').textContent = s.peak_pvs.toFixed(4) + ' in/s';
+        const when = s.peak_pvs_at ? s.peak_pvs_at.slice(0, 10) : '';
+        const who  = s.peak_pvs_serial || '';
+        document.getElementById('ev-stat-peak-when').textContent = [when, who].filter(Boolean).join(' · ') || '—';
+    } else {
+        document.getElementById('ev-stat-peak').textContent = '—';
+        document.getElementById('ev-stat-peak-when').textContent = '—';
+    }
+
+    if (s.last_event) {
+        const dt = s.last_event.slice(0, 19).replace('T', ' ');
+        document.getElementById('ev-stat-last').textContent = dt;
+    } else {
+        document.getElementById('ev-stat-last').textContent = '—';
+    }
+}
+
+function renderAssignmentsUsed(assignments) {
+    const card    = document.getElementById('events-assignments-card');
+    const listEl  = document.getElementById('ev-assignments-list');
+    const countEl = document.getElementById('ev-assignments-count');
+
+    if (!assignments || assignments.length === 0) {
+        card.classList.add('hidden');
+        return;
+    }
+    card.classList.remove('hidden');
+    countEl.textContent = `${assignments.length} assignment${assignments.length === 1 ? '' : 's'}`;
+
+    listEl.innerHTML = assignments.map(a => {
+        const start = a.assigned_at ? a.assigned_at.slice(0, 10) : '?';
+        const end   = a.assigned_until ? a.assigned_until.slice(0, 10) : 'present';
+        const isActive = !a.assigned_until;
+        const badge = isActive
+            ? '<span class="ml-2 px-2 py-0.5 rounded text-xs bg-green-100 text-green-800 dark:bg-green-900/30 dark:text-green-300">active</span>'
+            : '';
+        const editAttr = encodeURIComponent(JSON.stringify({
+            id: a.assignment_id,
+            unit_id: a.unit_id,
+            assigned_at: a.assigned_at,
+            assigned_until: a.assigned_until,
+        }));
+        return `<div class="py-2 flex items-center justify-between gap-3">
+            <div class="flex items-center gap-2 min-w-0">
+                <a href="/unit/${esc(a.unit_id)}" class="font-mono font-semibold text-seismo-orange hover:text-seismo-navy">${esc(a.unit_id)}</a>
+                ${badge}
+                <span class="text-sm text-gray-600 dark:text-gray-400">${start} → ${end}</span>
+                <button type="button"
+                        onclick="openAssignmentEditModal('${editAttr}')"
+                        title="Edit deployment dates"
+                        class="text-gray-400 hover:text-seismo-orange transition-colors p-1">
+                    <svg class="w-4 h-4" fill="none" stroke="currentColor" viewBox="0 0 24 24">
+                        <path stroke-linecap="round" stroke-linejoin="round" stroke-width="2" d="M11 5H6a2 2 0 00-2 2v11a2 2 0 002 2h11a2 2 0 002-2v-5m-1.414-9.414a2 2 0 112.828 2.828L11.828 15H9v-2.828l8.586-8.586z"></path>
+                    </svg>
+                </button>
+            </div>
+            <span class="text-sm text-gray-700 dark:text-gray-300 whitespace-nowrap">${(a.events_in_window || 0).toLocaleString()} event${a.events_in_window === 1 ? '' : 's'}</span>
+        </div>`;
+    }).join('');
+}
+
+// ── Assignment-edit modal ───────────────────────────────────────────────────
+function _isoToInputValue(iso) {
+    // Convert "2026-04-14T02:19:27" (or "2026-04-14 02:19:27") to "2026-04-14T02:19" for datetime-local input.
+    if (!iso) return '';
+    const cleaned = iso.replace(' ', 'T');
+    return cleaned.slice(0, 16);
+}
+
+function openAssignmentEditModal(encodedJson) {
+    const data = JSON.parse(decodeURIComponent(encodedJson));
+    document.getElementById('ae-assignment-id').value = data.id;
+    document.getElementById('ae-unit-label').textContent = data.unit_id;
+    document.getElementById('ae-assigned-at').value    = _isoToInputValue(data.assigned_at);
+    document.getElementById('ae-assigned-until').value = _isoToInputValue(data.assigned_until);
+    document.getElementById('ae-notes').value = '';
+    document.getElementById('ae-error').classList.add('hidden');
+    document.getElementById('assignment-edit-modal').classList.remove('hidden');
+}
+
+function closeAssignmentEditModal() {
+    document.getElementById('assignment-edit-modal').classList.add('hidden');
+}
+
+document.getElementById('assignment-edit-form').addEventListener('submit', async function(e) {
+    e.preventDefault();
+    const errEl = document.getElementById('ae-error');
+    errEl.classList.add('hidden');
+
+    const assignmentId = document.getElementById('ae-assignment-id').value;
+    const assignedAt    = document.getElementById('ae-assigned-at').value;
+    const assignedUntil = document.getElementById('ae-assigned-until').value;
+    const notes         = document.getElementById('ae-notes').value.trim();
+
+    if (!assignedAt) {
+        errEl.textContent = 'Assigned From is required.';
+        errEl.classList.remove('hidden');
+        return;
+    }
+
+    const payload = { assigned_at: assignedAt };
+    payload.assigned_until = assignedUntil || null;
+    if (notes) payload.notes = notes;
+
+    const btn = document.getElementById('ae-submit-btn');
+    btn.disabled = true; btn.textContent = 'Saving…';
+    try {
+        const r = await fetch(`/api/projects/${projectId}/assignments/${assignmentId}`, {
+            method:  'PATCH',
+            headers: {'Content-Type': 'application/json'},
+            body:    JSON.stringify(payload),
+        });
+        if (!r.ok) {
+            const err = await r.json().catch(() => ({detail: 'HTTP ' + r.status}));
+            throw new Error(err.detail || 'HTTP ' + r.status);
+        }
+        closeAssignmentEditModal();
+        await loadLocationEvents();   // Refresh stats + table with new window.
+    } catch (err) {
+        errEl.textContent = err.message || 'Failed to update assignment.';
+        errEl.classList.remove('hidden');
+    } finally {
+        btn.disabled = false; btn.textContent = 'Save';
+    }
+});
+
+document.getElementById('assignment-edit-modal').addEventListener('click', function(e) {
+    if (e.target === this) closeAssignmentEditModal();
+});
+
+function renderEventTable(events, total, container) {
+    if (!events || events.length === 0) {
+        const haveAssignments = !document.getElementById('events-assignments-card').classList.contains('hidden');
+        const msg = haveAssignments
+            ? 'No events recorded for the assignments above within the current filter.'
+            : 'No seismographs have been assigned to this location yet. Assign one to start collecting events.';
+        container.innerHTML = `<div class="text-center py-12 text-gray-500 dark:text-gray-400 text-sm">${msg}</div>`;
+        return;
+    }
+
+    const rows = events.map(ev => {
+        const ts = ev.timestamp ? ev.timestamp.replace('T', ' ').slice(0, 19) : '—';
+        const tran = fmtPPV(ev.tran_ppv);
+        const vert = fmtPPV(ev.vert_ppv);
+        const lng  = fmtPPV(ev.long_ppv);
+        const pvs  = fmtPPV(ev.peak_vector_sum);
+        const mic  = ev.mic_ppv != null ? ev.mic_ppv.toFixed(3) : '—';
+        const ft   = ev.false_trigger
+            ? '<span class="px-2 py-0.5 rounded text-xs bg-yellow-100 text-yellow-800 dark:bg-yellow-900/30 dark:text-yellow-300">FT</span>'
+            : '';
+
+        return `<tr class="hover:bg-gray-50 dark:hover:bg-slate-700/50">
+            <td class="px-4 py-2.5 text-sm text-gray-900 dark:text-white whitespace-nowrap">${ts}</td>
+            <td class="px-4 py-2.5 text-sm font-mono font-medium text-seismo-orange">
+                <a href="/unit/${esc(ev.serial)}" class="hover:text-seismo-navy">${esc(ev.serial)}</a>
+            </td>
+            <td class="px-4 py-2.5 text-sm font-mono ${ppvClass(ev.tran_ppv)}">${tran}</td>
+            <td class="px-4 py-2.5 text-sm font-mono ${ppvClass(ev.vert_ppv)}">${vert}</td>
+            <td class="px-4 py-2.5 text-sm font-mono ${ppvClass(ev.long_ppv)}">${lng}</td>
+            <td class="px-4 py-2.5 text-sm font-mono font-semibold ${ppvClass(ev.peak_vector_sum)}">${pvs}</td>
+            <td class="px-4 py-2.5 text-sm font-mono text-gray-600 dark:text-gray-400">${mic}</td>
+            <td class="px-4 py-2.5 text-sm">${ft}</td>
+        </tr>`;
+    }).join('');
+
+    container.innerHTML = `
+        <div class="text-xs text-gray-500 dark:text-gray-400 px-4 pt-3">Showing ${events.length} of ${total.toLocaleString()} events</div>
+        <table class="w-full text-left">
+            <thead class="bg-gray-50 dark:bg-slate-700 border-b border-gray-200 dark:border-gray-600">
+                <tr>
+                    <th class="px-4 py-3 text-xs font-medium text-gray-700 dark:text-gray-300 uppercase tracking-wider">Timestamp</th>
+                    <th class="px-4 py-3 text-xs font-medium text-gray-700 dark:text-gray-300 uppercase tracking-wider">Serial</th>
+                    <th class="px-4 py-3 text-xs font-medium text-gray-700 dark:text-gray-300 uppercase tracking-wider">Tran</th>
+                    <th class="px-4 py-3 text-xs font-medium text-gray-700 dark:text-gray-300 uppercase tracking-wider">Vert</th>
+                    <th class="px-4 py-3 text-xs font-medium text-gray-700 dark:text-gray-300 uppercase tracking-wider">Long</th>
+                    <th class="px-4 py-3 text-xs font-medium text-gray-700 dark:text-gray-300 uppercase tracking-wider">PVS</th>
+                    <th class="px-4 py-3 text-xs font-medium text-gray-700 dark:text-gray-300 uppercase tracking-wider">Mic</th>
+                    <th class="px-4 py-3 text-xs font-medium text-gray-700 dark:text-gray-300 uppercase tracking-wider">Flags</th>
+                </tr>
+            </thead>
+            <tbody class="divide-y divide-gray-200 dark:divide-gray-700">${rows}</tbody>
+        </table>`;
+}
+
+function fmtPPV(v) {
+    if (v == null) return '—';
+    return v.toFixed(4);
+}
+
+function ppvClass(v) {
+    if (v == null) return 'text-gray-400';
+    if (v < 0.5) return 'text-green-600 dark:text-green-400';
+    if (v < 2.0) return 'text-amber-600 dark:text-amber-400';
+    return 'text-red-600 dark:text-red-400 font-semibold';
+}
+
+function esc(s) {
+    if (s == null) return '';
+    return String(s).replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;').replace(/"/g, '&quot;');
 }
 
 // Location settings form submission