HISTORICAL TSUNAMI RECORDApril 11, 2012

Major Ocean Tsunami Generated (Historical Record)

This undersea earthquake generated recorded tsunami waves across coastal and trans-oceanic sectors. Preserved in seismic archive for scientific reference — no active hazard exists.

Seismic Event Dossier•14:38 Local (08:38 UTC)(14y ago)

M 8.6 earthquake
Indian Ocean (Indonesia)

A magnitude 8.6 (MW) earthquake occurred on 2012-04-11, 14:38 local time (08:38 UTC) (14y ago), centered Indian Ocean (437 km SW, Indonesia). The hypocenter was located at a shallow depth of 20 km. Primary telemetry verified by USGS/ISC-GEM.

Historical Landmark Earthquake

#50 of All Time

Curated Global Seismic Archive (1700–Present)

Top-100 Earthquakes

A magnitude 8.6 earthquake struck ⁨Indian Ocean (Indonesia)⁩ on 11 aprile 2012. Source: ⁨Wharton Basin Intraplate Shear⁩. Documented deaths: 10.

Documented Fatalities10Source: NOAA NCEI Significant Earthquake Database

Fault KinematicsStrike-Slip

Equivalent Energy119.79 Mt TNT

Magnitudo

M 8.6

119.79 Mt TNT

Profondità

20 km

shallow (Crostale superficiale)

Impatto PAGER

green

10 fatalities

Feriti: 50 – 500 · ~21.3M avvertito

Mappa interattiva di epicentro e faglie

2.33°N, 93.06°E

Faglia5 km

Wharton Basin Intraplate Shear

Strike-Slip · ~15.0 mm/yr

Felt byMMI III+

~21.3M exposed

~3.1M strong shaking

Primary SolutionUSGS/ISC-GEM

USGS/ISC-GEM#official20120411083836720_30reviewed

1 agencies reporting

Setting2.3°N

Indonesia

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 km (superficiale)35–70 km (intermedia)>70 km (profonda)Scossa principale

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

TSUNAMI WARNING

NOAA PTWC & regional buoys

Citizen Felt Reports

Not felt / offshore epicenter

Macroseismic DYFI verification

Aftershock Sequence

Monitoring

Aftershocks expected (Omori law)

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	M8.6(Mw)Ref	20.0 kmRef	2.33°, 93.06°Origin	Authoritative	official20120411083836720_30

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.

Tectonic setting

Nearest mapped active fault: Wharton Basin Intraplate Shear, 5 km away, slip rate ~15.0 mm/yr (GEM Global Active Faults).