4.2

M4.2 Earthquake 100 km SSE of Sand Point, Alaska — October 19, 2020

2020-10-19 23:04:23 UTC (2020-10-19) · approx. 12:04 PM UTC-11 local

MagnitudeM4.2(mb)
Time23:04 UTC≈ 12:04 PM UTC-11
Depth26.9 kmshallow crustal
Coordinates54.577°, -159.664°
Felt byNo felt reports
Status✓ Reviewed by USGS

On October 19, 2020 at 23:04 UTC, a magnitude 4.2 shallow crustal earthquake struck 100 km SSE of Sand Point, Alaska, at a depth of 26.9 km and coordinates 54.5770°, -159.6638°.

Physical scale: An earthquake of magnitude 4.2 releases seismic energy equivalent to roughly 30 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 476 m — a useful intuition for the size of the slip patch on the fault.

Map showing earthquake epicenter at 54.58°, -159.66°

Earthquake Details

Magnitude
4.2 mb
Depth
26.9 km
shallow crustal
Location
54.5770°N
-159.6638°E

Technical Information

Event ID
us6000c9pn
Event Type
earthquake
Status
✓ Reviewed
Significance
271
Azimuthal Gap
178.0°
Min Station Distance
0.258°
RMS Residual
1.01 sec
Last Updated
2020-12-29 23:07:47 UTC

Common Questions

How strong was the magnitude 4.2 earthquake near Sand Point, Alaska?

The magnitude 4.2 earthquake that struck 100 km SSE of Sand Point, Alaska on October 19, 2020 at 23:04 UTC had a depth of 26.9 km. For context, this was a light earthquake commonly felt near the epicenter.

Were there aftershocks?

Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.2 earthquakes can continue for several days and gradually diminish over time.

Understanding This Data

Magnitude 4.2 earthquakes are often felt but rarely cause damage.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: us6000c9pn). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2020, October 19, 2020). M4.2 Earthquake 100 km SSE of Sand Point, Alaska — October 19, 2020. Retrieved December 29, 2020 from https://www.earthquaketracker.org/earthquakes/event/us6000c9pn/