3.5

M3.5 Earthquake 60 km NNW of Yakutat, Alaska — March 11, 2021

2021-03-11 20:45:30 UTC (2021-03-11) · approx. 11:45 AM UTC-9 local

MagnitudeM3.5(ml)
Time20:45 UTC≈ 11:45 AM UTC-9
Depth3.9 kmshallow crustal
Coordinates60.028°, -140.230°
Felt byNo felt reports
Status✓ Reviewed by USGS

On March 11, 2021 at 20:45 UTC, a magnitude 3.5 shallow crustal earthquake struck 60 km NNW of Yakutat, Alaska, at a depth of 3.9 km and coordinates 60.0280°, -140.2304°.

Physical scale: An earthquake of magnitude 3.5 releases seismic energy equivalent to roughly 2.7 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 157 m — a useful intuition for the size of the slip patch on the fault.

Map showing earthquake epicenter at 60.03°, -140.23°

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 M3.5 earthquake near 60 km NNW of Yakutat, Alaska

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

Earthquake Details

Magnitude
3.5 ml
Depth
3.9 km
shallow crustal
Location
60.0280°N
-140.2304°E
Intensity (MMI)
4.5
moderate

Technical Information

Event ID
ak021383so43
Event Type
earthquake
Status
✓ Reviewed
Significance
188
RMS Residual
0.93 sec
Last Updated
2021-05-21 19:49:35 UTC

Common Questions

How strong was the magnitude 3.5 earthquake near Yakutat, Alaska?

The magnitude 3.5 earthquake that struck 60 km NNW of Yakutat, Alaska on March 11, 2021 at 20:45 UTC had a depth of 3.9 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 3.5 earthquakes can continue for several days and gradually diminish over time.

Understanding This Data

Magnitude 3.5 earthquakes are typically only recorded by instruments.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: ak021383so43). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2021, March 11, 2021). M3.5 Earthquake 60 km NNW of Yakutat, Alaska — March 11, 2021. Retrieved May 21, 2021 from https://www.earthquaketracker.org/earthquakes/event/ak021383so43/