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Seismic Event Dossier23:32 Local (03:32 UTC)(87y ago)

M 7.8 earthquake Chillán, Ñuble, Chile

A magnitude 7.8 (MW) earthquake occurred on 1939-01-25, 23:32 local time (03:32 UTC) (87y ago), centered 35 km N of Chillán (Chile). The hypocenter was located at a intermediate depth of 35 km. Primary telemetry verified by USGS.

Historical Landmark Earthquake

#32 of All Time

Curated Global Seismic Archive (1700–Present)

Top-100 Earthquakes

A magnitude 7.8 earthquake struck ⁨Chillán, Ñuble, Chile⁩ on 25 janvier 1939. Source: ⁨Peru–Chile Trench⁩. Documented deaths: 30,000.

Documented Fatalities30,000Source: NOAA NCEI Significant Earthquake Database
Fault KinematicsSubduction Megathrust
Equivalent Energy7.56 Mt TNT

Magnitude

MW
M 7.8

7.56 Mt TNT

Profondeur

35 km
35 km

intermediate (35–70 km (intermédiaire))

Impact PAGER

orange
100 – 1,000 fatalities

Blessés: > 5,000 · ~20M ressenti

Carte interactive de l'épicentre et des failles

36.30°S, 72.21°W
Faille104 km
Fosse du Pérou-Chili
Subduction Megathrust · ~15.0 mm/yr
Felt byMMI III+
~20M exposed
~2.8M strong shaking
Primary SolutionUSGS
USGS#iscgem901785reviewed
1 agencies reporting
Setting36.3°S
Chili central (Santiago et Valparaíso)
Continental / Inland crustal

Seismic Activity & Aftershock Sequence

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

M0.0M4.5M9.0100%50%0%Choc principal24 janv., 16 h25 janv., 04 h25 janv., 16 h26 janv., 04 h26 janv., 16 h27 janv., 04 h27 janv., 16 h28 janv., 04 hM7.8
Hover or tap a point to inspect aftershocks and risk probability curve.
<35 km (superficiel)35–70 km (intermédiaire)>70 km (profond)Choc principal

Situation Monitoring

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

Key facts so far

Casualties
Damage assessment in progress
Tsunami Status
No tsunami threat
NOAA PTWC & regional buoys
Citizen Felt Reports
0
No felt reports submitted
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 / SourceMagnitude (Scale & Diff)Depth & DiffEpicenter & Shift (Δd)ConsensusEvent ID / Data
USGS
United States Geological Survey · Global / US
M7.8(Mw)Ref
35.0 kmRef
-36.30°, -72.21°Origin
Authoritative
iscgem901785

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 localités

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

TownDistanceIntensity
Chillán · Ñuble35 kmMMI IX
Cauquenes · Maule39 kmMMI IX
Linares · Maule76 kmMMI VIII
Talcahuano · Bío-Bío93 kmMMI VIII
Concepción · Bío-Bío96 kmMMI VIII
Talca · Maule106 kmMMI VIII

Tectonic setting

Nearest mapped active fault: Peru–Chile Trench, 104 km away, slip rate ~15.0 mm/yr (GEM Global Active Faults).

Profil sismique régional

Chili central (Santiago et Valparaíso)

Consultez la surveillance sismique en direct, les références historiques de danger, les modèles de glissement des failles et les intervalles de récurrence pour cette zone.