M3.9 Earthquake 65 km ENE of Pedro Bay, Alaska — July 9, 2023
2023-07-09 20:57:48 UTC (2023-07-09) · approx. 10:57 AM UTC-10 local
On July 9, 2023 at 20:57 UTC, a magnitude 3.9 intermediate depth earthquake struck 65 km ENE of Pedro Bay, Alaska, at a depth of 127.6 km and coordinates 60.0313°, -153.0393°. The earthquake was reported felt by 3 peopleacross nearby locations, with a maximum shaking intensity of Modified Mercalli Intensity (MMI) 2.8 (weak).
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.
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.
Source: U.S. Geological Survey ShakeMap. View interactive ShakeMap on USGS
Did You Feel It? — community-reported shaking
Aggregated felt-report intensity from 3 citizen responses to the USGS Did You Feel It? system. Each colored zone represents the average MMI from reports in that area.
Source: U.S. Geological Survey Did You Feel It?. View on USGS · submit your own report
Earthquake Details
-153.0393°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 3.9 earthquake near Pedro Bay, Alaska?
The magnitude 3.9 earthquake that struck 65 km ENE of Pedro Bay, Alaska on July 9, 2023 at 20:57 UTC had a depth of 127.6 km. It was felt by 3 people with maximum shaking intensity of MMI 2.8 (weak). 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.
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Understanding This Data
Magnitude 3.9 earthquakes are typically only recorded by instruments.
Authoritative source: USGS event page (event ID: ak0238qkcxek). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, July 9, 2023). M3.9 Earthquake 65 km ENE of Pedro Bay, Alaska — July 9, 2023. Retrieved September 16, 2023 from https://www.earthquaketracker.org/earthquakes/event/ak0238qkcxek/