6.1

M6.1 Earthquake 90 km SW of Angaur State, Palau — December 23, 2020

2020-12-23 18:11:47 UTC (2020-12-23) · approx. 3:11 AM UTC+9 local

Felt by 20 people across nearby locations. Maximum shaking intensity MMI 4.5 (moderate).

MagnitudeM6.1(mww)
Time18:11 UTC≈ 3:11 AM UTC+9
Depth11.0 kmshallow crustal
Coordinates6.254°, 133.636°
Felt by20DYFI responses· max MMI 4.5
Status✓ Reviewed by USGS· green PAGER
green Alert— no significant casualties or damage expected

On December 23, 2020 at 18:11 UTC, a magnitude 6.1 shallow crustal earthquake struck 90 km SW of Angaur State, Palau, at a depth of 11.0 km and coordinates 6.2544°, 133.6362°. The earthquake was reported felt by 20 peopleacross nearby locations, with a maximum shaking intensity of Modified Mercalli Intensity (MMI) 4.5 (moderate). The USGS PAGER system issued a green alert level for this event, indicating no significant casualties or damage expected. The nearest populated place is Angaur State (population 188).

Physical scale: An earthquake of magnitude 6.1 releases seismic energy equivalent to roughly 21 kilotons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 9.7 km — a useful intuition for the size of the slip patch on the fault.

Nearest Populated Places

Angaur Statepop. 188
MMI 5.1 (strong)
Kloulklubedpop. 702
MMI 4.8 (moderate)
Ngchesar Hamletpop. 300
MMI 4.5 (moderate)
Sonsorol Villagepop. 30
MMI 4.5 (moderate)
Imeong Hamletpop. 132
MMI 4.5 (moderate)
Ulimangpop. 581
MMI 4.5 (moderate)
Map showing earthquake epicenter at 6.25°, 133.64°

ShakeMap — predicted shaking intensity

Modeled ground-motion intensity contoured on the Modified Mercalli scale (MMI). Computed by the USGS from the moment-tensor solution and regional ground-motion prediction equations.

USGS ShakeMap intensity contours for the M6.1 earthquake near 90 km SW of Angaur State, Palau

Source: U.S. Geological Survey ShakeMap. View interactive ShakeMap on USGS

Did You Feel It? — community-reported shaking

Aggregated felt-report intensity from 20 citizen responses to the USGS Did You Feel It? system. Each colored zone represents the average MMI from reports in that area.

USGS DYFI community-reported intensity map for the M6.1 earthquake near 90 km SW of Angaur State, Palau

Source: U.S. Geological Survey Did You Feel It?. View on USGS · submit your own report

Population exposure (USGS PAGER)

Estimated population that experienced each level of shaking. Based on the USGS PAGER rapid impact assessment, which combines ShakeMap output with global population grids.

Shaking intensity (MMI)DescriptionPopulation exposed
MMI 3weak1,108,537
MMI 4light30,433
MMI 5moderate923

Earthquake Details

Magnitude
6.1 mww
Depth
11.0 km
shallow crustal
Location
6.2544°N
133.6362°E
Felt Reports
20
DYFI responses
Intensity (MMI)
4.5
moderate
Community Intensity
5.0
CDI from reports

Technical Information

Event ID
us6000d29t
Event Type
earthquake
Status
✓ Reviewed
Significance
582
Azimuthal Gap
34.0°
Min Station Distance
1.561°
RMS Residual
0.99 sec
Last Updated
2025-12-22 18:47:17 UTC

Common Questions

How strong was the magnitude 6.1 earthquake near Angaur State, Palau?

The magnitude 6.1 earthquake that struck 90 km SW of Angaur State, Palau on December 23, 2020 at 18:11 UTC had a depth of 11.0 km. It was felt by 20 people with maximum shaking intensity of MMI 4.5 (moderate). For context, this was a strong earthquake capable of causing significant damage.

Where did the earthquake occur?

The earthquake epicenter was located at 6.2544°, 133.6362°, which is 90 km SW of Angaur State, Palau. The nearest populated place is Angaur State (population 188).

Were there aftershocks?

Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 6.1 earthquakes can continue for weeks to months and gradually diminish over time.

Authoritative source: USGS event page (event ID: us6000d29t). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2020, December 23, 2020). M6.1 Earthquake 90 km SW of Angaur State, Palau — December 23, 2020. Retrieved December 22, 2025 from https://www.earthquaketracker.org/earthquakes/event/us6000d29t/