3.5

M3.5 Earthquake 109 km SE of Perryville, Alaska — September 7, 2020

2020-09-07 20:08:47 UTC (2020-09-07) · approx. 9:08 AM UTC-11 local

MagnitudeM3.5(ml)
Time20:08 UTC≈ 9:08 AM UTC-11
Depth26.5 kmshallow crustal
Coordinates55.122°, -158.107°
Felt byNo felt reports
Status✓ Reviewed by USGS

On September 7, 2020 at 20:08 UTC, a magnitude 3.5 shallow crustal earthquake struck 109 km SE of Perryville, Alaska, at a depth of 26.5 km and coordinates 55.1217°, -158.1065°.

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 55.12°, -158.11°

Earthquake Details

Magnitude
3.5 ml
Depth
26.5 km
shallow crustal
Location
55.1217°N
-158.1065°E

Technical Information

Event ID
ak020bjfuld3
Event Type
earthquake
Status
✓ Reviewed
Significance
188
RMS Residual
0.52 sec
Last Updated
2020-11-17 19:44:52 UTC

Common Questions

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

The magnitude 3.5 earthquake that struck 109 km SE of Perryville, Alaska on September 7, 2020 at 20:08 UTC had a depth of 26.5 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: ak020bjfuld3). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2020, September 7, 2020). M3.5 Earthquake 109 km SE of Perryville, Alaska — September 7, 2020. Retrieved November 17, 2020 from https://www.earthquaketracker.org/earthquakes/event/ak020bjfuld3/