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Seismic Event Dossier01:46 Local (17:46 UTC)(78y ago)

M 7.8 earthquake Negros Occidental, Philippines

A magnitude 7.8 (MW) earthquake occurred on 1948-01-24, 01:46 local time (17:46 UTC) (78y ago), centered 82 km W of Bacolod (Philippines). The hypocenter was located at a shallow depth of 15 km. Primary telemetry verified by USGS.

Historical Landmark Earthquake

#91 of All Time

Curated Global Seismic Archive (1700–Present)

Top-100 Earthquakes

A magnitude 7.8 earthquake struck ⁨Negros Occidental, Philippines⁩ on January 24, 1948. Source: ⁨West Panay Fault⁩. Documented deaths: 74.

Documented Fatalities74Source: NOAA NCEI Significant Earthquake Database
Fault KinematicsActive Fault
Equivalent Energy7.56 Mt TNT

Magnitude

MW
M 7.8

7.56 Mt TNT

Depth

15 km
15 km

shallow (Shallow crustal)

PAGER Impact

red
> 1,000 fatalities

Injuries: > 5,000 · ~56.3M felt

Interactive Epicenter & Fault Map

10.71°N, 122.23°E
Fault5 km
West Panay Fault
Active Fault · ~15.0 mm/yr
Felt byMMI III+
~56.3M exposed
~11.2M strong shaking
Primary SolutionUSGS
USGS#iscgem897163reviewed
1 agencies reporting
Setting10.7°N
Mindanao Island & Trench
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%MainshockJan 27Feb 1Feb 6M7.8
Hover or tap a point to inspect aftershocks and risk probability curve.
<35 km (Shallow)35–70 km (Intermediate)>70 km (Deep)Mainshock
ML Risk Forecast:12h35%24h47%72h61%7d76%

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
Aftershocks: 2
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
M7.8(Mw)Ref
15.0 kmRef
10.71°, 122.23°Origin
Authoritative
iscgem897163

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 settlements

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

TownDistanceIntensity
Iloilo · Iloilo34 kmMMI IX
Bacolod · Negros Occidental82 kmMMI VIII
Roxas · Capiz112 kmMMI VIII
Cadiz · Negros Occidental120 kmMMI VII
Cebu · Cebu187 kmMMI VII
Ormac · Leyte262 kmMMI VI

Tectonic setting

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

Regional Seismic Profile

Mindanao Island & Trench

View live seismic monitoring, historical danger benchmarks, fault slip models and recurrence intervals for this zone.