3.8

M3.8 Earthquake 140 km S of False Pass, Alaska — June 16, 2021

2021-06-16 18:14:11 UTC (2021-06-16) · approx. 7:14 AM UTC-11 local

MagnitudeM3.8(mb)
Time18:14 UTC≈ 7:14 AM UTC-11
Depth35.0 kmshallow crustal
Coordinates53.590°, -163.507°
Felt byNo felt reports
Status✓ Reviewed by USGS

On June 16, 2021 at 18:14 UTC, a magnitude 3.8 shallow crustal earthquake struck 140 km S of False Pass, Alaska, at a depth of 35.0 km and coordinates 53.5904°, -163.5068°.

Physical scale: An earthquake of magnitude 3.8 releases seismic energy equivalent to roughly 7.6 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 252 m — a useful intuition for the size of the slip patch on the fault.

Map showing earthquake epicenter at 53.59°, -163.51°

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 M3.8 earthquake near 140 km S of False Pass, Alaska

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

Earthquake Details

Magnitude
3.8 mb
Depth
35.0 km
shallow crustal
Location
53.5904°N
-163.5068°E
Intensity (MMI)
1.0
weak

Technical Information

Event ID
us7000edll
Event Type
earthquake
Status
✓ Reviewed
Significance
222
Azimuthal Gap
209.0°
Min Station Distance
1.448°
RMS Residual
1.18 sec
Last Updated
2021-08-26 21:59:27 UTC

Common Questions

How strong was the magnitude 3.8 earthquake near False Pass, Alaska?

The magnitude 3.8 earthquake that struck 140 km S of False Pass, Alaska on June 16, 2021 at 18:14 UTC had a depth of 35.0 km. For context, this was a minor earthquake typically detected only by instruments.

Were there aftershocks?

Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 3.8 earthquakes can continue for several days and gradually diminish over time.

Understanding This Data

Magnitude 3.8 earthquakes are typically only recorded by instruments.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: us7000edll). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2021, June 16, 2021). M3.8 Earthquake 140 km S of False Pass, Alaska — June 16, 2021. Retrieved August 26, 2021 from https://www.earthquaketracker.org/earthquakes/event/us7000edll/