M3.1 Earthquake 91 km S of Sand Point, Alaska — July 18, 2025
2025-07-18 22:54:28 UTC (2025-07-18) · approx. 11:54 AM UTC-11 local
On July 18, 2025 at 22:54 UTC, a magnitude 3.1 shallow crustal earthquake struck 91 km S of Sand Point, Alaska, at a depth of 23.2 km and coordinates 54.5230°, -160.2686°.
Physical scale: An earthquake of magnitude 3.1 releases seismic energy equivalent to roughly 674 kg of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 83 m — a useful intuition for the size of the slip patch on the fault.
This earthquake is part of an ongoing aftershock sequence following the magnitude 5.0 mainshock that occurred 2 days ago 81 km S of Sand Point, Alaska. Since the mainshock, the USGS has recorded 10 aftershocks in this area. Aftershock activity is expected to continue for days to weeks as stresses on surrounding faults redistribute.
Earthquake Details
-160.2686°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 3.1 earthquake near Sand Point, Alaska?
The magnitude 3.1 earthquake that struck 91 km S of Sand Point, Alaska on July 18, 2025 at 22:54 UTC had a depth of 23.2 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 3.1 earthquakes can continue for several days and gradually diminish over time.
Is this the same earthquake as the M5.0 one earlier?
No. This magnitude 3.1 earthquake is an aftershock of the larger magnitude 5.0 mainshock that occurred earlier 81 km S of Sand Point, Alaska. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
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Understanding This Data
Magnitude 3.1 earthquakes are typically only recorded by instruments.
Authoritative source: USGS event page (event ID: us6000r0j7). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2025, July 18, 2025). M3.1 Earthquake 91 km S of Sand Point, Alaska — July 18, 2025. Retrieved October 3, 2025 from https://www.earthquaketracker.org/earthquakes/event/us6000r0j7/