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Seismic Event Dossier20:18 Local (12:18 UTC)(たった今)

M 8.3 earthquake Philippine Sea (Philippines)

A magnitude 8.3 (MW) earthquake occurred on 1918-08-15, 20:18 local time (12:18 UTC) (たった今), centered Philippine Sea (145 km SW of General Santos, Philippines). The hypocenter was located at a shallow depth of 20 km. Primary telemetry verified by USGS.

Historical Landmark Earthquake

#59 of All Time

Curated Global Seismic Archive (1700–Present)

Top-100 Earthquakes

A magnitude 8.3 earthquake struck ⁨Philippine Sea (Philippines)⁩ on 1918年8月15日. Source: ⁨Cotabato Trench⁩. Documented deaths: 52.

Documented Fatalities52Source: NOAA NCEI Significant Earthquake Database
Fault KinematicsSubduction Megathrust
Equivalent Energy42.50 Mt TNT

マグニチュード

MW
M 8.3

42.50 Mt TNT

震源の深さ

20 km
20 km

shallow (浅発・地殻内)

PAGER影響評価

red
> 1,000 fatalities

負傷者数: > 5,000 · ~52.1M 人が体感

震央・断層インタラクティブマップ

5.54°N, 123.99°E
断層5 km
Cotabato Trench
Subduction Megathrust · ~15.0 mm/yr
Felt byMMI III+
~52.1M exposed
~28.9M strong shaking
Primary SolutionUSGS
USGS#iscgem913230reviewed
1 agencies reporting
Setting5.5°N
ミンダナオ島・フィリピン海溝
Philippine Sea (海域)

Seismic Activity & Aftershock Sequence

Timeline of foreshocks, main rupture, aftershocks and machine learning risk probability evolution.

M0.0M4.5M9.0100%50%0%本震8月17日8月22日8月27日9月1日9月6日M8.3
Hover or tap a point to inspect aftershocks and risk probability curve.
<35 km (浅発・被害大)35–70 km（やや深い）>70 km (深発地震)本震
MLリスク予測:12h41%24h56%72h72%7d90%

Situation Monitoring

Continuous verification
Multi-agency verification of casualties, tsunami alerts, and seismic sequence

Key facts so far

Casualties
None expected (offshore epicenter)
Zero exposed population
Tsunami Status
No tsunami threat
NOAA PTWC & regional buoys
Citizen Felt Reports
0
Not felt / offshore epicenter
Macroseismic DYFI verification
Aftershock Sequence
Aftershocks: 6
High Omori aftershock probability
LightGBM hazard model forecast
Multi-agency seismic telemetry active. Awaiting wire headlines.

Agency Discrepancy Matrix (Cross-Network Verification)

Comparing multi-network solutions from primary and teleseismic monitoring agencies.

Network / SourceMagnitude (Scale & Diff)Depth & DiffEpicenter & Shift (Δd)ConsensusEvent ID / Data
USGS
United States Geological Survey · Global / US
M8.3(Mw)Ref
20.0 kmRef
5.54°, 123.99°Origin
Authoritative
iscgem913230

Why do agency magnitudes differ? Seismological agencies use different instrumentation networks, crustal velocity models, and mathematical magnitude scales (e.g. Moment Magnitude Mw vs Local Richter ML vs Surface Wave Ms). Differences of 0.1–0.3 are common and reflect physical observation geometry rather than errors.

Where it was felt

6 か所の集落

Shaking intensity is modelled from magnitude, depth and distance (GMPE attenuation), not reported by residents.

TownDistanceIntensity
General Santos · South Cotabato145 kmMMI VIII
Cotabato · Shariff Kabunsuan189 kmMMI VII
Davao · Davao Del Sur252 kmMMI VII
Zamboanga · Zamboanga del Sur262 kmMMI VII
Pagadian · Zamboanga Del Sur263 kmMMI VII
Ozamis · Misamis Occidental291 kmMMI VII

Tectonic setting

Nearest mapped active fault: Cotabato Trench, 5 km away, slip rate ~15.0 mm/yr (GEM Global Active Faults).

地域地震プロファイル

ミンダナオ島・フィリピン海溝

このゾーンのリアルタイム地震モニタリング、過去の危険基準、断層すべりモデル、再来周期を表示。