4.2

M4.2 Earthquake 51 km ESE of Mud Bay, AlaskaOctober 10, 2022

2022-10-10 23:48:01 UTC (2022-10-10) · approx. 2:48 PM UTC-9 local

Felt by 84 people across nearby locations.

MagnitudeM4.2(mb)
Time23:48 UTC2:48 PM UTC-9
Depth2.1 kmshallow crustal
Coordinates59.050°, -134.507°
Felt by84DYFI responses· max MMI 3.8
Status✓ Reviewed by USGS· Tsunami evaluation
Tsunami Warning Issued

On October 10, 2022 at 23:48 UTC, a magnitude 4.2 shallow crustal earthquake struck 51 km ESE of Mud Bay, Alaska, at a depth of 2.1 km and coordinates 59.0499°, -134.5066°. The earthquake was reported felt by 84 peopleacross nearby locations, with a maximum shaking intensity of Modified Mercalli Intensity (MMI) 3.8 (light).

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.

The epicenter is located in Alaska, a region characterized by Pacific Plate subduction beneath the North American Plate, producing frequent megathrust and crustal earthquakes along the Aleutian arc. The nearest mapped fault system is the Aleutian megathrust. View all earthquakes in Alaska.

Learn more: Magnitude scale · Aftershock sequences

Map showing earthquake epicenter at 59.05°, -134.51°

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 M4.2 earthquake near 51 km ESE of Mud Bay, Alaska

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

Did You Feel It? — community-reported shaking

Aggregated felt-report intensity from 84 citizen responses to the USGS Did You Feel It? system. Each colored zone represents the average MMI from reports in that area.

USGS DYFI community-reported intensity map for the M4.2 earthquake near 51 km ESE of Mud Bay, Alaska

Source: U.S. Geological Survey Did You Feel It?. View on USGS · submit your own report

Earthquake Details

Magnitude
4.2 mb
Depth
2.1 km
shallow crustal
Location
59.0499°N
-134.5066°E
Felt Reports
84
DYFI responses
Intensity (MMI)
3.8
light
Community Intensity
3.8
CDI from reports

Technical Information

Event ID
ak022d0f2h3p
Event Type
earthquake
Status
✓ Reviewed
Significance
303
RMS Residual
0.78 sec
Last Updated
2022-12-17 22:53:52 UTC

Common Questions

How strong was the magnitude 4.2 earthquake near Mud Bay, Alaska?

The magnitude 4.2 earthquake that struck 51 km ESE of Mud Bay, Alaska on October 10, 2022 at 23:48 UTC had a depth of 2.1 km. It was felt by 84 people with maximum shaking intensity of MMI 3.8 (light). For context, this was a light earthquake commonly felt near the epicenter.

Where did the earthquake occur?

The earthquake epicenter was located at 59.0499°, -134.5066°, which is 51 km ESE of Mud Bay, Alaska. View all earthquakes in Alaska.

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.

Has Alaska had earthquakes this big before?

The largest recorded earthquake in Alaska was the M9.2 Great Alaska earthquake of March 27, 1964. Today's magnitude 4.2 event is significantly smaller than that historical record.

Authoritative source: USGS event page (event ID: ak022d0f2h3p). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2022, October 10, 2022). M4.2 Earthquake 51 km ESE of Mud Bay, AlaskaOctober 10, 2022. Retrieved December 17, 2022 from https://www.earthquaketracker.org/earthquakes/event/ak022d0f2h3p/