3.9

M3.9 Earthquake 174 km ESE of Chignik, AlaskaOctober 28, 2024

2024-10-28 20:04:00 UTC (2024-10-28) · approx. 10:04 AM UTC-10 local

MagnitudeM3.9(mwr)
Time20:04 UTC10:04 AM UTC-10
Depth9.4 kmshallow crustal
Coordinates55.518°, -155.977°
Felt byNo felt reports
Status✓ Reviewed by USGS

On October 28, 2024 at 20:04 UTC, a magnitude 3.9 shallow crustal earthquake struck 174 km ESE of Chignik, Alaska, at a depth of 9.4 km and coordinates 55.5176°, -155.9773°.

Physical scale: An earthquake of magnitude 3.9 releases seismic energy equivalent to roughly 11 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 296 m — a useful intuition for the size of the slip patch on the fault.

Map showing earthquake epicenter at 55.52°, -155.98°

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 M3.9 earthquake near 174 km ESE of Chignik, Alaska

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

Earthquake Details

Magnitude
3.9 mwr
Depth
9.4 km
shallow crustal
Location
55.5176°N
-155.9773°E
Intensity (MMI)
2.5
weak

Technical Information

Event ID
ak024dvs88t2
Event Type
earthquake
Status
✓ Reviewed
Significance
234
RMS Residual
0.63 sec
Last Updated
2025-01-16 18:44:35 UTC

Common Questions

How strong was the magnitude 3.9 earthquake near Chignik, Alaska?

The magnitude 3.9 earthquake that struck 174 km ESE of Chignik, Alaska on October 28, 2024 at 20:04 UTC had a depth of 9.4 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 3.9 earthquakes can continue for several days and gradually diminish over time.

Understanding This Data

Magnitude 3.9 earthquakes are typically only recorded by instruments.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: ak024dvs88t2). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2024, October 28, 2024). M3.9 Earthquake 174 km ESE of Chignik, AlaskaOctober 28, 2024. Retrieved January 16, 2025 from https://www.earthquaketracker.org/earthquakes/event/ak024dvs88t2/