5.6

M5.6 Earthquake 188 km SSE of Alo, Wallis and Futuna — June 6, 2021

2021-06-06 18:24:30 UTC (2021-06-06) · approx. 6:24 AM UTC-12 local

MagnitudeM5.6(mww)
Time18:24 UTC≈ 6:24 AM UTC-12
Depth432.0 kmdeep-focus
Coordinates-15.871°, -177.411°
Felt byNo felt reports
Status✓ Reviewed by USGS· green PAGER
green Alert— no significant casualties or damage expected

On June 6, 2021 at 18:24 UTC, a magnitude 5.6 deep-focus earthquake struck 188 km SSE of Alo, Wallis and Futuna, at a depth of 432.0 km and coordinates -15.8711°, -177.4115°. The USGS PAGER system issued a green alert level for this event, indicating no significant casualties or damage expected. The nearest populated place is Alo (population 239).

Physical scale: An earthquake of magnitude 5.6 releases seismic energy equivalent to roughly 4 kilotons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 4.4 km — a useful intuition for the size of the slip patch on the fault.

Nearest Populated Places

Alopop. 239
MMI 1.4 (weak)
Sigavepop. 480
MMI 1.4 (weak)
Map showing earthquake epicenter at -15.87°, -177.41°

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 M5.6 earthquake near 188 km SSE of Alo, Wallis and Futuna

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)DescriptionPopulation exposed

Earthquake Details

Magnitude
5.6 mww
Depth
432.0 km
deep-focus
Location
-15.8711°N
-177.4115°E
Intensity (MMI)
1.9
weak

Technical Information

Event ID
us7000eaib
Event Type
earthquake
Status
✓ Reviewed
Significance
482
Azimuthal Gap
64.0°
Min Station Distance
1.698°
RMS Residual
0.99 sec
Last Updated
2025-12-22 19:02:17 UTC

Common Questions

How strong was the magnitude 5.6 earthquake near Alo, Wallis and Futuna?

The magnitude 5.6 earthquake that struck 188 km SSE of Alo, Wallis and Futuna on June 6, 2021 at 18:24 UTC had a depth of 432.0 km. For context, this was a moderate earthquake that could be widely felt.

Where did the earthquake occur?

The earthquake epicenter was located at -15.8711°, -177.4115°, which is 188 km SSE of Alo, Wallis and Futuna. The nearest populated place is Alo (population 239).

Were there aftershocks?

Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 5.6 earthquakes can continue for days to weeks and gradually diminish over time.

Authoritative source: USGS event page (event ID: us7000eaib). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2021, June 6, 2021). M5.6 Earthquake 188 km SSE of Alo, Wallis and Futuna — June 6, 2021. Retrieved December 22, 2025 from https://www.earthquaketracker.org/earthquakes/event/us7000eaib/