M5.7 Earthquake 241 km SSE of Alo, Wallis and Futuna — December 21, 2020
2020-12-21 17:08:55 UTC (2020-12-21) · approx. 5:08 AM UTC-12 local
On December 21, 2020 at 17:08 UTC, a magnitude 5.7 shallow crustal earthquake struck 241 km SSE of Alo, Wallis and Futuna, at a depth of 10.0 km and coordinates -16.3994°, -177.4622°. The USGS PAGER system issued a green alert level for this event, indicating no significant casualties or damage expected.
Physical scale: An earthquake of magnitude 5.7 releases seismic energy equivalent to roughly 5 kilotons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 5.2 km — a useful intuition for the size of the slip patch on the fault.
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.
Source: U.S. Geological Survey ShakeMap. View interactive ShakeMap on USGS
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) | Description | Population exposed |
|---|---|---|
| MMI 3 | weak | 4,261 |
Earthquake Details
-177.4622°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 5.7 earthquake near Alo, Wallis and Futuna?
The magnitude 5.7 earthquake that struck 241 km SSE of Alo, Wallis and Futuna on December 21, 2020 at 17:08 UTC had a depth of 10.0 km. For context, this was a moderate earthquake that could be widely felt.
Where did the earthquake occur?
The earthquake epicenter was located at -16.3994°, -177.4622°, which is 241 km SSE of Alo, Wallis and Futuna.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 5.7 earthquakes can continue for days to weeks and gradually diminish over time.
Actions
Authoritative source: USGS event page (event ID: us6000d1pw). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2020, December 21, 2020). M5.7 Earthquake 241 km SSE of Alo, Wallis and Futuna — December 21, 2020. Retrieved December 22, 2025 from https://www.earthquaketracker.org/earthquakes/event/us6000d1pw/