3.3

M3.3 Earthquake 19 km ESE of Chignik, Alaska — May 9, 2021

2021-05-09 23:34:00 UTC (2021-05-09) · approx. 12:34 PM UTC-11 local

MagnitudeM3.3(ml)
Time23:34 UTC≈ 12:34 PM UTC-11
Depth96.4 kmintermediate depth
Coordinates56.233°, -158.109°
Felt byNo felt reports
StatusAutomatic (preliminary)

On May 9, 2021 at 23:34 UTC, a magnitude 3.3 intermediate depth earthquake struck 19 km ESE of Chignik, Alaska, at a depth of 96.4 km and coordinates 56.2325°, -158.1089°.

Physical scale: An earthquake of magnitude 3.3 releases seismic energy equivalent to roughly 1.3 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 114 m — a useful intuition for the size of the slip patch on the fault.

Map showing earthquake epicenter at 56.23°, -158.11°

Earthquake Details

Magnitude
3.3 ml
Depth
96.4 km
intermediate depth
Location
56.2325°N
-158.1089°E

Technical Information

Event ID
ak0215xq80zc
Event Type
earthquake
Status
Automatic
Significance
168
RMS Residual
0.83 sec
Last Updated
2021-07-23 18:08:27 UTC

Common Questions

How strong was the magnitude 3.3 earthquake near Chignik, Alaska?

The magnitude 3.3 earthquake that struck 19 km ESE of Chignik, Alaska on May 9, 2021 at 23:34 UTC had a depth of 96.4 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 3.3 earthquakes can continue for several days and gradually diminish over time.

Understanding This Data

Magnitude 3.3 earthquakes are typically only recorded by instruments.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: ak0215xq80zc). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2021, May 9, 2021). M3.3 Earthquake 19 km ESE of Chignik, Alaska — May 9, 2021. Retrieved July 23, 2021 from https://www.earthquaketracker.org/earthquakes/event/ak0215xq80zc/