4.2

M4.2 Earthquake near Alaska PeninsulaJuly 2, 2023

2023-07-02 22:47:05 UTC (2023-07-02) · approx. 12:47 PM UTC-10 local

MagnitudeM4.2(mwr)
Time22:47 UTC12:47 PM UTC-10
Depth12.7 kmshallow crustal
Coordinates57.771°, -155.965°
Felt by1DYFI response· max MMI 4.3
Status✓ Reviewed by USGS

On July 2, 2023 at 22:47 UTC, a magnitude 4.2 shallow crustal earthquake struck near Alaska Peninsula, at a depth of 12.7 km and coordinates 57.7708°, -155.9649°. The earthquake was reported felt by 1 personacross nearby locations, with a maximum shaking intensity of Modified Mercalli Intensity (MMI) 4.3 (moderate).

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 57.77°, -155.96°

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 Alaska Peninsula

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

Did You Feel It? — community-reported shaking

Aggregated felt-report intensity from 1 citizen response 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 Alaska Peninsula

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

Earthquake Details

Magnitude
4.2 mwr
Depth
12.7 km
shallow crustal
Location
57.7708°N
-155.9649°E
Felt Reports
1
DYFI responses
Intensity (MMI)
4.3
moderate
Community Intensity
2.0
CDI from reports

Technical Information

Event ID
ak0238f0q4pu
Event Type
earthquake
Status
✓ Reviewed
Significance
272
RMS Residual
0.65 sec
Last Updated
2023-09-09 21:54:38 UTC

Common Questions

How strong was the magnitude 4.2 earthquake near Alaska Peninsula?

The magnitude 4.2 earthquake that struck near Alaska Peninsula on July 2, 2023 at 22:47 UTC had a depth of 12.7 km. It was felt by 1 person with maximum shaking intensity of MMI 4.3 (moderate). 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: ak0238f0q4pu). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2023, July 2, 2023). M4.2 Earthquake near Alaska PeninsulaJuly 2, 2023. Retrieved September 9, 2023 from https://www.earthquaketracker.org/earthquakes/event/ak0238f0q4pu/