M4.0 Earthquake 25 km W of Salamatof, Alaska — June 20, 2022
2022-06-20 19:09:51 UTC (2022-06-20) · approx. 9:09 AM UTC-10 local
On June 20, 2022 at 19:09 UTC, a magnitude 4.0 intermediate depth earthquake struck 25 km W of Salamatof, Alaska, at a depth of 75.0 km and coordinates 60.6161°, -151.7926°. The nearest populated place is Cohoe (population 1,364).
Physical scale: An earthquake of magnitude 4.0 releases seismic energy equivalent to roughly 15 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 347 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
Population exposure (USGS PAGER)
Estimated population that experienced each level of shaking. Based on the USGS PAGER rapid impact assessment, which combines ShakeMap output with global population grids.
| Shaking intensity (MMI) | Description | Population exposed |
|---|---|---|
| MMI 3 | weak | 84,098 |
Earthquake Details
-151.7926°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.0 earthquake near Salamatof, Alaska?
The magnitude 4.0 earthquake that struck 25 km W of Salamatof, Alaska on June 20, 2022 at 19:09 UTC had a depth of 75.0 km. 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 4.0 earthquakes can continue for several days and gradually diminish over time.
Actions
Understanding This Data
Magnitude 4.0 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: ak0227v49mcw). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2022, June 20, 2022). M4.0 Earthquake 25 km W of Salamatof, Alaska — June 20, 2022. Retrieved August 28, 2022 from https://www.earthquaketracker.org/earthquakes/event/ak0227v49mcw/