TSRATectonic Strain Ratchet Analyzer

Cotabato · Sarangani
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Evidence grammar
Official row PHIVOLCS public bulletin record Final association directly inspected bulletin statement Inference bounded interpretation, not official classification Local note private observation · never merged automatically
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Baseline Pulse
35.55 min
Fitted stick-slip period
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Confirmed Events
11
Observation notes separate
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Last Confirmed
03:36 AM
Jun 10, 2026 · A10
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Model Fit
88.9 %
Calibration-derived timing alignment
Bounded sequence state · inference

Loading the reviewed sequence snapshot…

Claim status Derived from a fixed public-catalog capture, not a live warning state.
Loading reviewed snapshot
Captured
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Coverage begins
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Last included row
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Research area 4.2–6.2°N · 124.5–126.0°E
Association boundary AOI inclusion is not an official associated-aftershock flag.
Freshness Reviewed static snapshot · never presented as live.
Official rows
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Deduplicated inside the declared AOI
M4 and above
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Magnitude hierarchy, not felt count
M5 and above
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Five stronger releases in the window
M6 and above
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Final PHIVOLCS magnitude values
Sequence timeline · mainshock anchor + bounded capture

Decay, renewal, and magnitude structure

Download 1,202-row ledger
Below M2 M2–2.9 M3–3.9 M4–4.9 M5+ Mainshock anchor Partial day No reviewed coverage
Rate reading Waiting for verified daily activity.
Coverage boundary Waiting for capture metadata.
Claim ceiling Waiting for source boundary.
Spatial branch reading · bounded inference

Event volume and stronger releases occupy different parts of the sequence.

Waiting for verified spatial branches.

Final PHIVOLCS solutions

Significant releases · M4.5 and above

Download final-bulletin ledger

Magnitude type, value, depth, location, intensity, and source remain specific to each final PHIVOLCS bulletin. Preliminary and USGS values are not silently merged.

Time · PHT Final magnitude Depth Final location Max intensity Source
Interpretation boundary The branches are transparent latitude-based research groups, not named faults, rupture segments, or official PHIVOLCS cluster classifications.
Verified PHIVOLCS catalog · lazy loaded

Official event ledger

1,202 deduplicated public bulletin rows inside the declared research AOI: the directly reviewed June 8 mainshock anchor plus continuous capture from June 30 through the partial July 22 snapshot. June 9–29 remains an explicit no-data gap. AOI inclusion is not an official associated-aftershock flag.

Open Ledger to load catalog Download complete CSV
Separate local recordPrivate observation notebook 0 local records
Historical local notes and private device records remain physically separate from the official PHIVOLCS catalog. They are never counted as official events or automatic sequence evidence.
Source Report Time Context Relation Outcome Status
FELTLocal felt · low certainty · pending official check Jun 10 · by ~09:55 AM 09:13 AM extended-phase watch Earlier / uncertain Significant felt activity Pending PHIVOLCS
OBSLocal outcome · no-shake · not official Jun 10 · 02:03 PM 7.0× long-phase watch Watch center elapsed No local outcome observed Elapsed
OBSLocal outcome · no-shake · not official Jun 10 · 03:32 PM 9.5× extended-phase watch Watch center elapsed No local outcome observed Elapsed
FELTLocal felt-only · low certainty · pattern context Jun 10 · ~05:14 PM 05:37 PM phase-sensitive watch Before the watch time; ~23 min before anchor Brief local shake felt Felt-only
FELTLocal felt-only · low certainty · pattern context Jun 10 · ~07:36 PM 07:41 PM 7.0× long-phase watch Before the watch time; ~5 min before anchor Subtle local movement felt for ~1 min Felt-only
OBSLocal outcome · no-shake · not official Jun 10 · 09:10 PM 9.5× extended-phase watch Nothing happened during the watch No local shake observed Elapsed
FELTLocal felt-only · low certainty · anchor candidate Jun 10 · ~11:47 PM 3.5× phase-sensitive watch After the watch time; ~32 min after anchor Subtle local movement noticed for brief Felt-only
OBSLocal outcome · no-shake · not official Jun 11 · 12:54 PM 9.5× extended-phase watch Nothing happened during the watch No local shake observed through the morning after the final watch Elapsed
FELTLocal felt-only · low certainty · pattern context Jun 11 · ~03:34 PM 3.5× phase-sensitive watch After the watch time; ~36 min after anchor Local shake noticed underneath around 03:34 PM for brief Felt-only
OBSLocal outcome · no-shake · not official Jun 11 · 09:11 PM 9.5× extended-phase watch Nothing happened during the watch No observation report for now; no local shake observed during the watch Elapsed
OBSLocal outcome · no-shake · not official Jun 11 · 09:46 PM 1.0× post-anchor watch Nothing happened during the watch No local shake observed during the elapsed watch Elapsed
OBSLocal outcome · no-shake · not official Jun 12 · 01:54 AM 7.0× long-phase watch Nothing happened during the watch No local shake observed during the elapsed watch Elapsed
OBSLocal outcome · no-shake · not official Jun 12 · 07:31 AM 9.5× extended-phase watch Nothing happened during the watch No local observation around the four elapsed observation windows Elapsed
OBSLocal outcome · no-shake · not official Jun 12 · 01:08 PM 9.5× extended-phase watch Nothing happened during the watch No local observation around the four elapsed observation windows Elapsed
FELTLocal felt-only · low certainty · pattern context Jun 13 · ~01:24 AM 9.5× extended-phase watch After the watch time; ~398 min after anchor Consistent subtle local shake felt by observer; felt-only local observation, not an official seismic confirmation Felt-only
FELTLocal felt-only · low certainty · pattern context Jun 13 · ~10:07 AM 9.5× extended-phase watch After the watch time; ~185 min after anchor Clear local shake felt by observer around 10:07 AM; felt-only local observation, not an official seismic confirmation Felt-only
OBSLocal outcome · no-shake · not official Jun 13 · 03:44 PM 9.5× extended-phase watch Nothing happened during the watch All prior windows elapsed; no new local shake reported Elapsed
FELTLocal felt-only · low certainty · pattern context Jun 14 · ~07:30 AM 9.5× extended-phase watch After the watch time; ~608 min after anchor Subtle local shake felt by observer around 7:30 AM; felt-only local observation, not an official seismic confirmation Felt-only
OBSLocal outcome · no-shake · not official Jun 14 · 01:07 PM 9.5× extended-phase watch Nothing happened during the watch All prior windows elapsed; no new local shake reported Elapsed
OBSLocal outcome · no-shake · not official Jun 14 · 06:45 PM 9.5× extended-phase watch Nothing happened during the watch All prior windows elapsed; no new local shake reported Elapsed
OBSLocal outcome · no-shake · not official Jun 15 · 12:23 AM 9.5× extended-phase watch Nothing happened during the watch All prior windows elapsed; no new local shake reported Elapsed
OBSLocal outcome · no-shake · not official Jun 15 · 06:00 AM 9.5× extended-phase watch Nothing happened during the watch All prior windows elapsed; no new local shake reported Elapsed
OBSLocal outcome · no-shake · not official Jun 15 · 11:38 AM 9.5× extended-phase watch Nothing happened during the watch All prior windows elapsed; no new local shake reported Elapsed
FELTLocal felt-only · low certainty · pattern context Jun 15 · ~05:20 PM 9.5× extended-phase watch Around the watch time Strong local shake felt by observer around 5:20 PM for at least 6 seconds; subjectively closer to a 7.0×-or-less felt class; felt-only local observation, not an official seismic confirmation Felt-only
OBSLocal outcome · no-shake · not official Jun 15 · 10:57 PM 9.5× extended-phase watch Nothing happened during the watch All prior windows elapsed; no new local shake reported Elapsed
FELTLocal felt-only · low certainty · pattern context Jun 15 · ~11:30 PM 1.0× post-anchor watch Around the watch time Subtle local shake felt by observer around 11:30 PM, slightly before the 1.0× watch center; felt-only local observation, not an official seismic confirmation Felt-only
OBSLocal outcome · no-shake · not official Jun 16 · 05:07 AM 9.5× extended-phase watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 16 · 01:35 PM 9.5× extended-phase watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 16 · 07:12 PM 9.5× extended-phase watch Nothing happened during the watch No local shake observed through the evening; all prior watches elapsed Elapsed
OBSLocal outcome · no-shake · not official Jun 17 · 12:49 AM 9.5× extended-phase watch Nothing happened during the watch No local shake observed through the night; all watches elapsed Elapsed
OBSLocal outcome · no-shake · not official Jun 17 · 06:26 AM 9.5× extended-phase watch Nothing happened during the watch No local shake observed through the early morning; all prior watches elapsed Elapsed
OBSLocal outcome · no-shake · not official Jun 17 · 07:01 AM 1.0× post-anchor watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 17 · 08:30 AM 3.5× phase-sensitive watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 17 · 10:34 AM 7.0× long-phase watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 17 · 12:03 PM 9.5× extended-phase watch Nothing happened during the watch No local shake observed through the midday; all prior watches elapsed Elapsed
OBSLocal outcome · no-shake · not official Jun 17 · 12:38 PM 1.0× post-anchor watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 17 · 02:07 PM 3.5× phase-sensitive watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 17 · 04:11 PM 7.0× long-phase watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 17 · 05:40 PM 9.5× extended-phase watch Nothing happened during the watch No local shake observed through the afternoon; all prior watches elapsed Elapsed
OBSLocal outcome · no-shake · not official Jun 17 · 06:16 PM 1.0× post-anchor watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 17 · 07:45 PM 3.5× phase-sensitive watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 17 · 09:49 PM 7.0× long-phase watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 17 · 11:18 PM 9.5× extended-phase watch Nothing happened during the watch No local shake observed through the evening; all prior watches elapsed Elapsed
OBSLocal outcome · no-shake · not official Jun 17 · 11:54 PM 1.0× post-anchor watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 18 · 01:22 AM 3.5× phase-sensitive watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 18 · 03:27 AM 7.0× long-phase watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 18 · 04:55 AM 9.5× extended-phase watch Nothing happened during the watch No local shake observed through the early morning; all prior watches elapsed Elapsed
OBSLocal outcome · no-shake · not official Jun 18 · 05:30 AM 1.0× post-anchor watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 18 · 06:59 AM 3.5× phase-sensitive watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 18 · 09:03 AM 7.0× long-phase watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 18 · 10:32 AM 9.5× extended-phase watch Nothing happened during the watch No local shake observed through the morning; all prior watches elapsed Elapsed
OBSLocal outcome · no-shake · not official Jun 18 · 11:07 AM 1.0× post-anchor watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 18 · 12:36 PM 3.5× phase-sensitive watch Nothing happened during the watch No local shake observed Elapsed
FELTLocal felt-only · low certainty · pattern context Jun 18 · ~02:58 PM 7.0× long-phase watch After the watch time; ~17 min after anchor Not-subtle local shake felt by observer around 2:58 PM for about 6 seconds Felt-only
OBSLocal outcome · no-shake · not official Jun 18 · 03:33 PM 1.0× first post-anchor observation watch Nothing happened during the watch Model-generated watch elapsed; no local shake outcome recorded Elapsed
OBSLocal outcome · no-shake · not official Jun 18 · 05:02 PM 3.5× phase-sensitive observation watch Nothing happened during the watch Model-generated watch elapsed; no local shake outcome recorded Elapsed
OBSLocal outcome · no-shake · not official Jun 18 · 07:06 PM 7.0× long-phase observation watch Nothing happened during the watch Model-generated watch elapsed; no local shake outcome recorded Elapsed
OBSLocal outcome · no-shake · not official Jun 18 · 08:35 PM 9.5× extended-phase observation watch Nothing happened during the watch Latest observation outcome remains elapsed; model window generated watch, not warning Elapsed
FELTLocal felt-only · unresolved · bounded official check Jun 20 · ~02:39 AM Separate felt-only observation Outside confirmed event log Subtle local shake felt by observer for about 5 seconds; bounded PHIVOLCS/public check did not find a matched official row Unresolved
FELTLocal felt-only · low certainty · pattern context Jun 26 · ~07:56 AM 1.0× post-anchor watch After the watch time; ~1160 min after anchor Subtle local shake felt this morning around 7:56 AM for about 2 sec Felt-only
OBSLocal outcome · no-shake · not official Jun 26 · 01:33 PM 9.5× extended-phase watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 26 · 01:34 PM 9.5× extended-phase watch Nothing happened during the watch No local shake observed Elapsed
FELTLocal felt-only · low certainty · pattern context Jun 26 · ~07:45 PM 9.5× extended-phase watch After the watch time; ~33 min after anchor Strong earthquake event felt for ~6-7 seconds for 6-7 sec Felt-only
OBSLocal outcome · no-shake · not official Jun 27 · 01:22 AM 9.5× extended-phase watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 27 · 06:59 AM 9.5× extended-phase watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 27 · 12:36 PM 9.5× extended-phase watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 27 · 06:13 PM 9.5× extended-phase watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 27 · 11:50 PM 9.5× extended-phase watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 28 · 05:27 AM 9.5× extended-phase watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 28 · 11:04 AM 9.5× extended-phase watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 28 · 04:41 PM 9.5× extended-phase watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 28 · 10:18 PM 9.5× extended-phase watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 29 · 03:55 AM 9.5× extended-phase watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 29 · 09:32 AM 9.5× extended-phase watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 29 · 03:09 PM 9.5× extended-phase watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 29 · 08:46 PM 9.5× extended-phase watch Nothing happened during the watch No local shake observed Elapsed
OBSLocal outcome · no-shake · not official Jun 30 · 02:23 AM 9.5× extended-phase watch Nothing happened during the watch No local shake observed Elapsed
Historical hypothesis audit

A useful early observation, preserved without countdown authority.

Waiting for the reviewed method record.

Fitted baseline —

Original selected-event least-squares value.

Acceptance band —

A wide descriptive tolerance, not a warning interval.

Uniform null occupancy —

Chance phase coverage from the rounded 35.55-minute baseline.

Selected calibration —

Waiting for original investigation data.

Why the early fit looked persuasive

Selection, fitting, and tolerance compressed the search.

  1. The baseline and multiplier classes were fitted from a small selected sequence.
  2. The ±12-minute band covers approximately 67.5% of every rounded cycle.
  3. Aftershocks are temporally clustered, so independent uniform-phase assumptions are not physically adequate.
  4. Mixing northern microevents with southern strong releases can create alignments that do not belong to one source clock.
Operational decision

Retain the hypothesis; remove the forecast behavior.

35.55 minutes remains visible because it records how the investigation began. It no longer generates watches, re-anchors cycles, marks events imminent, or controls safety-facing state.

Current organizing modelPunctuated aftershock decay with spatially distinct subclusters.
Expanded catalog test

Threshold-specific interval audit

Descriptive p-values · not an independent ETAS/Omori comparison
Threshold Events Median spacing Within ±12 min Null occupancy Descriptive p Reading
Original page provenance

The selected 11-event investigation

Waiting for timestamp boundary.
Label Displayed time · PHT Selected interval Nearest phase Offset Historical result
Limitations carried forward
    Claim ceiling

    The historical alignment does not establish a deterministic recurrence period, earthquake prediction capability, magnitude forecast, named controlling structure, or official sequence completeness.

    Historical artifactThis timing chart is preserved as provenance. It is not a current forecast or validated fault clock.
    Dashboard Chart
    Light-theme TSRA timing chart showing phase accumulation behavior and observer versus instrument timing drift

    How to read the chart

    Read the dashboard as a timing diary. It shows when confirmed events happened, how far apart they were, and where the current observation windows sit relative to the fitted pulse rhythm.

    1

    The main rhythm is a repeated phase-rise/reset pattern: elapsed timing accumulates, then an event or local watch outcome resets the visual index.

    2

    The labeled phase bands organize time. They do not certify that shaking will happen or how strong it will be.

    3

    Confirmed events, felt reports, and model watch windows stay separate so the chart remains useful without overstating certainty.

    Reading the Chart — Plain Language Guide

    Sawtooth rhythm

    Rising lines mark elapsed phase accumulation. Drops mark a reset in the timing index after an observed event or local watch outcome.

    Peak height

    Higher peaks mean longer phase intervals, not guaranteed stronger shaking. Amplitude is logged separately.

    Phase markers

    1×, 3.5×, 7×, and 9.5× organize timing around a fitted 35.5-minute pulse.

    Observer vs instrument

    Human notes and official records stay separate, then comparable. Agreement strengthens the timing read.

    Historical material · non-operational

    The earlier interpretation remains inspectable, but it no longer governs the instrument.

    These surfaces preserve how the 35.55-minute hypothesis was originally seen, explained, and communicated. They are provenance—not current sequence state, prediction evidence, or safety guidance.

    Current authority Sequence for reviewed state Method for the clock audit PHIVOLCS for official guidance
    05 · Separate research artifact TMCH Slab2 convergence gate A standalone archive retained at its authored route and kept outside the current sequence data contract.
    Archive claim ceiling

    Archived language and graphics may contain obsolete assumptions, selected-event reasoning, provisional tectonic attribution, or predictive framing. Their presence records the investigation; it does not validate those claims.

    Historical artifactThis disclosure preserves TSRA’s early framing. Current scope and limits are defined by Sequence and Method.
    Reading context · after the 1,202-row review TSRA no longer opens watch windows, re-anchors cycles, or maintains observation timing state. The instrument is now a static, source-bounded observatory of the reviewed PHIVOLCS catalog. This disclosure is preserved to show the tool’s original purpose and boundary language; the current scope is defined by Sequence and Method, and official guidance remains with PHIVOLCS.
    Description

    A field record for timing, not a warning system.

    observation archive

    TSRA is an observational timing tool built from field notes, confirmed event timestamps, and a fitted phase model. Its purpose is to organize rhythm: what was confirmed, what was felt, and which watch windows are worth observing next.

    01 Confirmed events

    Official or instrument-backed seismic records stay in the event log so the baseline remains clean.

    02 Felt observations

    Human reports are logged separately when timing matters but confirmation is still pending.

    03 Watch windows

    The model marks timing bands for observation only; it does not certify an event or estimate magnitude.

    Important: TSRA is not a certified warning system, magnitude predictor, or substitute for PHIVOLCS advisories, civil defense instructions, or professional seismological assessment. Treat every window here as context for observation only: useful for noticing rhythm, never enough for safety decisions by itself.
    Historical artifactThese narrated modules retain provisional rhythm language and are not source evidence or current guidance.
    Learning Guide
    Tectonic field notes, one plate at a time.
    01 / 02
    Field module · 01
    Subduction & Trench Mechanics
    A landscape guide to trench rhythm, phase windows, and why felt observations are logged separately from confirmed seismic events.
    07:59 · narration source
    Video unavailableThe local safety video did not load. Confirm /safety/Cotabato_Trench_Rhythm.mp4 is included in the deployed project.
    Timed transcript
    0001 / 0000Whisper Large v3 Turbo · M4A source
    00:0000:00

    Machine transcript generated from the local M4A narration source. Active words follow the video playback time; review proper nouns against source context when needed.

    Field module · 02
    Twin Tectonic Giants
    A companion guide for reading the larger tectonic systems behind local reports, fault rhythm, and provisional watch-window interpretation.
    01:52 · narration source
    Video unavailableThe local safety video did not load. Confirm /safety/Twin_Tectonic_Giants.mp4 is included in the deployed project.
    Timed transcript
    0001 / 0000Whisper Large v3 Turbo · M4A source
    00:0000:00

    Machine transcript generated from the local M4A narration source. Active words follow the video playback time; review proper nouns against source context when needed.

    Use < / > to move between learning plates. Only one guide is shown at a time.
    Superseded interpretationThis report contains claims that do not survive the expanded-catalog audit. Preserve it as history; do not use it for prediction, safety, or current sequence interpretation.
    Reading context · after the 1,202-row review The expanded catalog did not validate a single-period clock. The 35.55-minute baseline, its multiplier windows, and the 88.9% fit survive below as the record of how the investigation began — not as current interpretation. The current organizing model is punctuated aftershock decay with spatially distinct microevent and strong-release populations; see Sequence and Method. All figures below, including the stated mainshock magnitude, are preserved exactly as originally written and were not re-verified by the review.
    Seismic Pulse Jun 8, 2026  ·  Mw 7.8  ·  Cotabato Trench
    26 km WSW of Kablalan, Sarangani  ·  Epicentral Intensity VIII

    On the morning of June 8, 2026, a magnitude 7.8 earthquake struck the Cotabato Trench boundary off the southwestern coast of Mindanao. What followed was not a random scatter of aftershocks. It was a structured sequence — one that kept returning to the same timing intervals, hours apart and across two days, in a way that only a locked fault under constant pressure can produce.

    The fault that does not release smoothly

    Stick-slip under 100 mm/year

    The Cotabato Trench is one of the fastest-loading subduction boundaries in the Pacific region. The Celebes Sea floor dives eastward beneath Mindanao at roughly 100 millimetres every year — that is 10 centimetres of compression every 12 months, relentlessly applied to a megathrust interface that spans hundreds of kilometres.

    The fault does not absorb this pressure gradually and slip away quietly. Instead, high-friction patches called asperities lock the interface in place. Elastic strain accumulates in the surrounding rock until the locking force is overcome. Then the patch snaps — a stick-slip release — and the cycle begins again from zero.

    The 1918 Celebes Sea earthquake (Ms 8.3) and the 1976 Moro Gulf earthquake (Mw 8.1) both originated from this same boundary. The 2026 sequence is not an anomaly in the historical record; it is the record continuing.

    The rhythm that emerged

    35 minutes, then its multiples

    After the mainshock, the aftershocks arrived at intervals that proved non-random. A3 and A4 — two consecutive events on the same afternoon — each arrived exactly 35.0 minutes after the previous event. Within 37 seconds of the fitted 35.55-minute baseline. Twice in a row.

    The larger gaps held the same structure at longer range: A1 arrived 334 minutes after the mainshock (9.5× = 337.7 min, delta −3.4 min). A2 and A5 both arrived 244 minutes after their predecessors (7.0× = 248.9 min, delta −4.9 min). A6 arrived 126 minutes later (3.5× = 124.4 min, delta +1.6 min).

    The system appears to discharge at discrete multiples of the base interval: 1×, 3.5×, 7×, and 9.5×. These are not values derived from a published equation. They are what the Cotabato data produced, and the fit to them is what TSRA measures.

    What the observation model does

    A watch instrument, not a forecast

    TSRA takes the fitted 35.55-minute baseline and opens four phase windows after each confirmed event. When the next event arrives, it either lands inside a window or it does not. The model re-anchors after every confirmed hit and keeps the next set of windows open for observation.

    This is not a seismic forecast in the scientific sense. There is no magnitude estimate, no rupture probability, no claim about whether a window will produce anything locally felt. The model is a timing instrument for watching whether the structural rhythm continues to hold.

    During an active sequence, knowing when to look more carefully is itself useful — especially for people living close to the source zone who have no access to real-time institutional monitoring.

    Where the model held and where it broke

    7 of 9, one honest miss

    Close (≤5 min) 7 of 9 intervals
    Moderate (6–10 min) 1 A8 +7.4 min
    Miss (>10 min) 1 A7 −28 min early
    Model fit 88.9% calibration-derived

    A7 is the honest anomaly: it arrived 28 minutes before the predicted 3.5× window. The ratchet slipped early on that cycle. The model re-anchored, and by A9 the sequence was back within 5 minutes of the 1× slot. The rhythm re-asserted itself after the perturbation — which is itself a meaningful observation about the fault’s mechanical consistency.

    A10, a 10-minute sub-pulse after A9, falls outside the standard phase model entirely. Short-lag releases closely coupled to the preceding event are common in complex aftershock sequences and are not what TSRA is designed to watch for.

    What this does not tell us

    Honest limits

    The model is built on 11 confirmed events across a roughly 44-hour window. That is enough to fit a baseline and open watch windows, but not enough to treat the multiplier pattern as a permanent feature of this fault’s behaviour. Two forward-looking windows on the afternoon of June 10 elapsed without a locally felt outcome, and the 09:10 PM extended-phase watch also elapsed with no local shake observed. Felt observations at ~05:14 PM and ~07:36 PM remain useful timing notes, but they are not confirmed seismic events.

    TSRA does not know how much strain remains stored. It does not know whether the next window will produce surface motion strong enough to feel. It does not substitute for PHIVOLCS advisories, civil defence instructions, or professional seismological assessment. What it does is keep the timing record visible during an active sequence, in plain language, for anyone watching the ground.

    Academic grounding — literature-search-arxiv
    • [0910.3738] Aftershock magnitude time distribution and fault geometry fingerprinting — supports the premise that aftershock temporal patterns carry a fault-specific signature rather than being random. arxiv.org/abs/0910.3738
    • [0803.4263] Aftershock sequence statistics and fault geometry — cumulative magnitude integral forms a predictable linear trend, consistent with systematic rather than chaotic stress release. arxiv.org/abs/0803.4263
    • [1004.1924] Spatiotemporal correlations of aftershock sequences — enhanced seismic activity shows structured temporal clustering, not uniform decay. arxiv.org/abs/1004.1924
    • [cond-mat/0012058] Model for complex aftershock sequences — Omori law governs rate decay; the multiplier spacing observed here is a distinct structural phenomenon, not contradicted by Omori but not predicted by it either. arxiv.org/abs/cond-mat/0012058
    • [1909.06787] Silent energy buildup precedes slow slip failure, Cascadia — structured strain accumulation patterns before failure in locked subduction zones. arxiv.org/abs/1909.06787
    Audit note — The geological framework (DDS, Cotabato Trench asperity model, stick-slip mechanism) is academically grounded. The specific 1×/3.5×/7×/9.5× multiplier framework is an empirical observation from this sequence and is not derived from or validated by a published theoretical model. The calibration-derived 88.9% timing fit is computed from 9 standard confirmed intervals; A10 remains visible but excluded as a sub-pulse. Treat forward windows as observational structure, not certified forecasts.