5.5

M5.5 Earthquake 227 km S of Sand Point, Alaska — July 5, 2020

2020-07-05 08:53:34 UTC (2020-07-05) · approx. 9:53 PM UTC-11 local

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MagnitudeM5.5(mww)
Time08:53 UTC≈ 9:53 PM UTC-11
Depth10.0 kmshallow crustal
Coordinates53.296°, -160.418°
Felt byNo felt reports
Status✓ Reviewed by USGS· Tsunami evaluation· green PAGER
green Alert— no significant casualties or damage expected
Tsunami Warning Issued

On July 5, 2020 at 08:53 UTC, a magnitude 5.5 shallow crustal earthquake struck 227 km S of Sand Point, Alaska, at a depth of 10.0 km and coordinates 53.2962°, -160.4182°. The USGS PAGER system issued a green alert level for this event, indicating no significant casualties or damage expected.

Physical scale: An earthquake of magnitude 5.5 releases seismic energy equivalent to roughly 3 kilotons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 3.8 km — a useful intuition for the size of the slip patch on the fault.

The epicenter is located in Alaska, a region characterized by Pacific Plate subduction beneath the North American Plate, producing frequent megathrust and crustal earthquakes along the Aleutian arc. The nearest mapped fault system is the Aleutian megathrust. View all earthquakes in Alaska.

Learn more: Magnitude scale · Aftershock sequences

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Map showing earthquake epicenter at 53.30°, -160.42°

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 M5.5 earthquake near 227 km S of Sand Point, Alaska

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

Earthquake Details

Magnitude
5.5 mww
Depth
10.0 km
shallow crustal
Location
53.2962°N
-160.4182°E
Intensity (MMI)
0.0
weak

Technical Information

Event ID
us7000ai7p
Event Type
earthquake
Status
✓ Reviewed
Significance
465
Azimuthal Gap
40.0°
Min Station Distance
1.613°
RMS Residual
0.60 sec
Last Updated
2025-12-22 18:37:32 UTC

Common Questions

How strong was the magnitude 5.5 earthquake near Sand Point, Alaska?

The magnitude 5.5 earthquake that struck 227 km S of Sand Point, Alaska on July 5, 2020 at 08:53 UTC had a depth of 10.0 km. For context, this was a moderate earthquake that could be widely felt.

Where did the earthquake occur?

The earthquake epicenter was located at 53.2962°, -160.4182°, which is 227 km S of Sand Point, Alaska. View all earthquakes in Alaska.

Were there aftershocks?

Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 5.5 earthquakes can continue for days to weeks and gradually diminish over time.

Has Alaska had earthquakes this big before?

The largest recorded earthquake in Alaska was the M9.2 Great Alaska earthquake of March 27, 1964. Today's magnitude 5.5 event is significantly smaller than that historical record.

Authoritative source: USGS event page (event ID: us7000ai7p). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2020, July 5, 2020). M5.5 Earthquake 227 km S of Sand Point, Alaska — July 5, 2020. Retrieved December 22, 2025 from https://www.earthquaketracker.org/earthquakes/event/us7000ai7p/