Brian noticed BE12599's 2026-08-09 event reports no ZC frequency because the
trace never crosses zero. That is the best detector in this investigation.
A geophone has no DC response, so its output must integrate to ~zero over a
record. |mean|/peak is therefore ~0 for real motion and ~1 for anything
electrical. Across 12,068 channel-events with peak >= 0.05 in/s the statistic
is bimodal with a 1.09% dead zone, and at mp >= 0.8 it returns exactly the five
confirmed units -- from physics rather than a tuned threshold. Two detectors on
different principles agreeing is the strongest corroboration the list has had.
It also settles BE11007 as NOT an offset: mp 0.75-0.89 but frac_neg 0.99 at
peaks of 7.4-9.4 in/s, i.e. a one-sided near-full-scale blast.
Journal 8e diagnoses BE12599 specifically. Its August waveforms are unipolar
impulses with an RC tail (26 ms -> 118 ms -> never recovers over 14 days), and
the fault MOVES between Long and Tran while the sensor self-check passes on
every event. A failing element cannot hop channels; a connector can -- which
also explains why the swing test never fails and why an autozero rarely helps.
Corrects 8c's claim that the spread gate is blind to onsets: of 87 BE18438|Vert
events it rejected one, the transitional record. Narrower than stated.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HgTe8CamXAHcAmaQ6QNcog
Records the mechanism investigation in journal 8c. The headline: still unknown,
but the shape is now constrained and a long list of dead ends is closed.
Onset is a ramp of minutes-to-hours, not a step — BE18438 Vert resolved to
one-minute cadence via the histogram corpus, 50% of the excursion in 7 minutes,
>=25 intermediates, validated 75/75 against Blastware's own ASCII. That kills
both poles of the original dichotomy: not a latched digital step, not slow
component wear. What survives is a reversible two-time-constant settling
process, which is a shape constraint and not a mechanism.
Thermal, ground-motion shock, handling/redeployment, accumulated duty, age,
firmware and a mechanical element fault are each refuted or explicitly bounded,
with the power behind every negative stated.
Retracts two claims this journal carried: polarity consistency was a tautology
of offset_scan3's spread gate, and the fleet is 8-9 units rather than 5 once
that gate is dropped. Also notes the gate is blind to onsets by construction --
it rejects a moving floor, and it rejected the one record where the ramp shows.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HgTe8CamXAHcAmaQ6QNcog
The release is bumped but not tagged, and the fix is now in dev — which is
what gets built — so the notes would otherwise understate the build. No
TOOL_VERSION change: the fix alters which serial an import is filed under,
not any decoded value, so no backfill is owed.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HgTe8CamXAHcAmaQ6QNcog
Two things, both starting from the same root cause.
The BW filename encodes the serial NUMBER only; the two-letter family prefix
is not in it. Every offset scanner synthesised "BE", which mislabels the four
BlastMates in the archive (BA9229, BA10060, BA10895, BA15957) and — in the
store's import path — would have filed a BlastMate under a unit that does not
exist. BlastMates are Series III and byte-identical to MiniMate Plus, so the
serial string was the only thing blocking SFM support; reading it from the
file body is the whole fix.
Separately, the archive's 63,535 histograms were scanned for offsets for the
first time. The result is largely a documented dead end — the detector finds
2 of the 5 confirmed units and a clean histogram is not evidence of health —
but it produced the BA10895 reclassification and a labelling caveat on
offset_scan3's spread gate. Journal §8b.
BA9229, BA10060, BA10895 and BA15957 were reported throughout as BE — the
scanners synthesised the family prefix, which the BW filename does not carry.
Corrected across the journal with a note recording why, so the mistake is
legible rather than silently patched.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01HgTe8CamXAHcAmaQ6QNcog
Bumps TOOL_VERSION 0.28.0 -> 0.29.0 and pyproject/CLAUDE/README 0.27.0 -> 0.29.0,
and dates the CHANGELOG section. v0.28.0 (offset DC-baseline detector) was
version-bumped in-tree but never tagged or deployed, so 0.29.0 is the first build
to carry both it and the false_trigger_reason column to prod.
Pairs with Terra-View >= 0.24.0. false_trigger_reason auto-migrates on startup;
the offset detector needs the shape backfill (scripts/backfill_event_shape.py) on
the prod store to populate shape_offset* on existing rows.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01YDXjZCr4RqT2U3QvMDhgzf
**50% of the excursion in 7 minutes**, the rest asymptotic over ~10 h, **>=25
distinct one-minute intermediates**. Validated **75/75** against Blastware's own
ASCII export. Its 2025-11-15 onset is the same shape over 2.7 h. BE13117 stage B
is a 91-minute monotone rise, +0.035 → +1.745 in/s over ~40 samples.
**This kills both poles of the original dichotomy** (journal Q1): not an
instantaneous latched step (a bad autozero, a stuck trim-DAC), and not slow
component degradation over days or weeks.
⚠ It rests on **2 of 45 instruments**. Clopper-Pearson on 4/4 resolved onsets
gives 95% CI [0.40, 1.00] — a mixed population with up to 60% true steps is not
excluded. BE13117 has zero paired ASCII, so its ramp rests on our decoder alone.
### The methodological corollary — more important than the finding
**A waveform-only bracket manufactures the appearance of a step, and the spread
gate is blind to onsets by construction.**
The offset is what fires the trigger, so no waveform event can exist until the
ramp has nearly reached the trigger level. BE18438's first event of each episode
sits at 0.280 against a 0.300 trigger, and 0.185 against 0.200. At daily cadence
against a 3 h ramp, P(catching an intermediate) = **0.125**.
And `spread <= 0.02` rejects any record in which the floor is *moving* — which
is exactly what an onset is. **The gate rejected the very BE18438 record where
the ramp is visible.** If the operational goal is catching a fault early, before
the unit floods the store with junk events, the current detector is the wrong
shape for the job.
### The surviving shape
An **electrical, reversible, two-time-constant settling process** (~10 min and
~hours), saturating at a ceiling, with occasional sub-3-minute discrete jumps
superposed (BE18438 2026-02-26: 13:24 pre +0.180 / mid +0.240 / end +0.255 →
13:27 +0.325, identical metadata). That is the signature of a **bias or leakage
path charging a high-impedance node** — the class of fault Instantel's autozero
recovers ~10% of the time, and what the X1/X8 gains measure.
**It is a shape constraint, not a mechanism. Do not write it up as one.**
### Dead — with the evidence, so none of this is re-derived
| Killed | Evidence |
|---|---|
| **Latched step at onset** | >=25 one-minute intermediates over ~10 h, ASCII-validated. Direct observation, not a test. |
| **Slow degradation over days/weeks** | Same observation — bulk of the excursion in 7 min to 2.7 h. |
| **Thermal driving of pedestal magnitude** | BE13117, 365-count pedestal, n=128: full-day modulation **−0.42% ± 0.42%**, 95% CI [−1.25%, +0.40%]. Healthy-fleet seasonal zero drift totals **~0.3 A/D counts** — 15x to 1200x too small. Best-powered result in the campaign. |
| **Ground-motion shock** | 30-day window-max percentile ranks 0.03/0.98/0.15/0.01/0.68/0.24, median **0.194** against a null of 0.5. **0 of 7 events >=9 in/s** was followed by an onset within 30 d. BE12599 hit 10.220 in/s (2023-11) and 10.005 (2025-04) and did not onset until 2026-08-14. |
| **Handling / redeployment** | **0 of 9** onsets had a Project/Client/Seis Loc change. Widened to 30 d: 2 observed vs 4.90 expected, P(X>=2)=0.995 — *depleted*, the wrong direction. The apparent gap effect (p=0.035) died on histogram coverage: BE18438's "59.7-day gap" contains 122 histogram files; true silence 0.52 d. |
| **Mechanical resonance / damping change** | BE18438|Vert at a 64-count pedestal (3x outside Instantel's ±21): ΔTest-Freq **CI [−0.090, +0.021]** against 0.127 Hz for a real calibration. Block permutation p=0.658. |
| **Accumulated-duty threshold** | ~4 clean units logged more monitoring than the largest positive onset dose; BE18193 logged **13.45M intervals, 6.2x**. A counterexample — no power argument weakens it. |
| **Firmware** | **14,338 of 14,340** exports read `V 10.72-8.17`. A constant cannot explain a variable. |
| **Unit age** | Serial rank-sum 118.0 vs null 115.0, p=0.549; unchanged on the 8-unit re-cut (p=0.586). Serial is a poor age proxy anyway (Spearman +0.113 against archive entry). |
| 2026-09-04 | **Histogram corpus scanned** — 63,505 of 63,535 files, 43 units, 77.9M intervals (9.7x the waveform corpus). `scratch/offset_hist_scan.py`. |
| 2026-09-04 | **Histogram corpus scanned** — 63,505 of 63,535 files, 43 units, 77.9M intervals (9.7x the waveform corpus). `scratch/offset_hist_scan.py`. |
| 2026-09-04 | Absolute-floor statistic **retired**: 66% of its discrimination is a day/site confound (other-channels-only AUC 0.746 vs 0.872). Zero-fraction shown **structurally impossible** — the device clamps every interval peak at >= 1 count. |
| 2026-09-04 | Absolute-floor statistic **retired**: 66% of its discrimination is a day/site confound (other-channels-only AUC 0.746 vs 0.872). Zero-fraction shown **structurally impossible** — the device clamps every interval peak at >= 1 count. |
| 2026-09-04 | Site-quiet-gated cross-channel differential established: **BE18438 Vert, BE9558 Tran+Long**, threshold-insensitive over a 2.3x span. Finds only **2 of the 5** confirmed units — leakage into the histogram floor is bimodal (0.9 to 0.02), so a negative result carries almost no information. Per-channel attribution **not** established (channel-scramble p = 0.769). |
| 2026-09-04 | Site-quiet-gated cross-channel differential established: **BE18438 Vert, BE9558 Tran+Long**, threshold-insensitive over a 2.3x span. Finds only **2 of the 5** confirmed units — leakage into the histogram floor is bimodal (0.9 to 0.02), so a negative result carries almost no information. Per-channel attribution **not** established (channel-scramble p = 0.769). |
| 2026-09-04 | **BE10895 reclassified** from transient to a genuine Vert fault of a different subtype — 49.4% single-axis-dominant events, the highest in the fleet, 100% on Vert. The other six marginal units are clean. |
| 2026-09-04 | **BA10895 reclassified** from transient to a genuine Vert fault of a different subtype — 49.4% single-axis-dominant events, the highest in the fleet, 100% on Vert. The other six marginal units are clean. |
| 2026-09-04 | **Defect found in `offset_scan3.py`**: its `spread <= 0.02` gate discards 18.8% of rows with \|pre\| >= 0.025, concentrated on 41 negative unit-channels; 4 would be sustained positives without it. The fleet label is three-state, not two. |
| 2026-09-04 | **Defect found in `offset_scan3.py`**: its `spread <= 0.02` gate discards 18.8% of rows with \|pre\| >= 0.025, concentrated on 41 negative unit-channels; 4 would be sustained positives without it. The fleet label is three-state, not two. |
| 2026-09-06 | **Four units relabelled BA, not BE** — BA9229, BA10060, BA10895, BA15957 are BlastMates. The BW filename carries only the serial number; the family prefix must be read from the file body. Fixed in the scanners and in two production sites. |
| 2026-09-06 | **Mechanism campaign — five hypotheses, all dead.** Thermal, ground-motion shock, handling/redeployment, accumulated duty, unit age, firmware and a mechanical element fault are each refuted or bounded. 7 nominally significant results against 5.2 expected by chance. |
| 2026-09-06 | **Onset is a RAMP of minutes-to-hours, not a step** — BE18438 Vert resolved to one-minute cadence, 50% of the excursion in 7 min, >=25 intermediates, ASCII-validated 75/75. Kills both a latched digital step AND slow component degradation. Surviving shape: a reversible two-time-constant settling process — a bias/leakage path charging a high-impedance node. |
| 2026-09-06 | **Polarity consistency RETRACTED** (a tautology of the spread gate; amplitude-only gives 12 of 53 unit-channels mixed) and the fleet **re-cut to 8–9 units, not 5**. "Persistent until serviced" weakened: 23 recoveries, median gap 6 days — though a field autozero cannot be excluded. |
| 2026-09-06 | The spread gate is **blind to onsets by construction** — it rejects a moving floor, which is what an onset is. It rejected the very record in which the ramp is visible. |
| 2026-09-07 | **The non-motion test** (Brian: "it doesn't cross zero"). `\|mean\|/peak` is bimodal with a 1.09% dead zone and returns exactly the 5 confirmed units from physics, not a threshold. Independent corroboration of the unit list. **BE11007 settled as NOT an offset** — a one-sided 9 in/s blast. |
| 2026-09-07 | **BE12599 is a connector fault, not a geophone fault.** Unipolar spikes with a 26→118 ms RC tail progressing to a flat pedestal, and the fault MOVES between Long and Tran while the sensor self-check passes on every event. An element cannot hop channels; a connector can. Inspect before reseating. |
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