Seismic Event Dossier•23:22 Local (13:22 UTC)(32y ago)

M 8.3 earthquake
North Pacific Ocean (Japan)

A magnitude 8.3 (MW) earthquake occurred on 1994-10-04, 23:22 local time (13:22 UTC) (32y ago), centered North Pacific Ocean (254 km E, Japan). The hypocenter was located at a shallow depth of 14 km. Primary telemetry verified by USGS.

Historical Landmark Earthquake

#95 of All Time

Curated Global Seismic Archive (1700–Present)

Top-100 Earthquakes

A magnitude 8.3 earthquake struck ⁨North Pacific Ocean (Japan)⁩ on 4 अक्टूबर 1994. Source: ⁨Kuril–Kamchatka Trench⁩. Documented deaths: 11.

Documented Fatalities11Source: NOAA NCEI Significant Earthquake Database

Fault KinematicsSubduction Megathrust

Equivalent Energy42.50 Mt TNT

तीव्रता

M 8.3

42.50 Mt TNT

गहराई

14 km

shallow (उथली भूपर्पटी)

PAGER प्रभाव

red

> 1,000 fatalities

घायल: > 5,000 · ~12.1M महसूस

इंटरैक्टिव उपरिकेंद्र और फ़ॉल्ट मानचित्र

43.77°N, 147.32°E

फ़ॉल्ट5 km

कुरील–कामचटका गर्त

Subduction Megathrust · ~15.0 mm/yr

Felt byMMI III+

~12.1M exposed

~2.6M strong shaking

Primary SolutionUSGS

USGS#usp0006kdpreviewed

1 agencies reporting

Setting43.8°N

Japan

Offshore / Marine rupture

Seismic Activity & Aftershock Sequence

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

Hover or tap a point to inspect aftershocks and risk probability curve.

<35 किमी (उथला)35–70 किमी (मध्यम)>70 किमी (गहरा)मुख्य झटका

ML जोखिम पूर्वानुमान:12h41%24h55%72h71%7d89%

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

Not felt / offshore epicenter

Macroseismic DYFI verification

Aftershock Sequence

Aftershocks: 50

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 / Source	Magnitude (Scale & Diff)	Depth & Diff	Epicenter & Shift (Δd)	Consensus	Event ID / Data
USGS United States Geological Survey · Global / US	M8.3(Mw)Ref	14.0 kmRef	43.77°, 147.32°Origin	Authoritative	usp0006kdp

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

2 बस्तियाँ

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

Town	Distance	Intensity	जनसंख्या
Kushiro · Hokkaido	254 km	MMI VII	198,566
Kitami · Hokkaido	275 km	MMI VII	113,137

Tectonic setting

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

M 8.3 earthquake North Pacific Ocean (Japan)