Earthquake · reviewed by a seismologist
M 5.1mww
Alaska Peninsula
Yes. A magnitude 5.1 earthquake was recorded in the Alaska Peninsula, at 10:59 am AKDT on 30 August 2023 (18:59 UTC), 47 km deep. 5 people have reported feeling it to USGS.
- When
- Magnitude
- M 5.1 (mww)
- Depth
- 47 km below the surface
- Felt
- 5 reports · strongest reported intensity III
- Measured shaking
- intensity III (ShakeMap)
- Nearest
- Aleutians East Borough, 69 km NW
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1105 days ago
Earthquake alerts for Sand Point, AK
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Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
This was a moderate earthquake. Shaking at this size can damage poorly built structures close to the epicentre.
At this magnitude and depth, people at rest would likely notice it out to about 200 km (124 mi) from the epicentre. Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.
How big was it?
This earthquake released about 670 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 6.1 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 250× the energy of this one
- Mineral, Virginia 2011 M 5.8 11× the energy of this one
- Magna, Utah 2020 M 5.7 7.9× the energy of this one
- This earthquake M 5.1 about 670 tons of TNT
- Around the size people start to feel M 3.0 this one released 1,400× more
Energy from the Gutenberg–Richter relation (log10E = 1.5M + 4.8), rounded to two figures; bar length is magnitude, which is already a logarithm of energy. Magnitudes of past earthquakes from the USGS catalogue.
For this area
The largest earthquake within 50 km in our catalogue was M 6.1 on 2020-07-28 — about 32 times the energy of this one.
Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.
Where
Epicentre 54.8166, -161.2124. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Aleutians East Borough, AK | 69 km (43 mi) | NW | earthquakes near Aleutians East Borough |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
57 earthquakes have been recorded within 50 km since this one.
- 2.3 89 km SE of King Cove, Alaska
- 3.4 86 km SSW of Sand Point, Alaska
- 1.6 74 km SSW of Sand Point, Alaska
- 1.7 83 km SSW of Sand Point, Alaska
- 1.8 90 km SSW of Sand Point, Alaska
- 1.6 86 km SSW of Sand Point, Alaska
- 1.6 68 km SE of King Cove, Alaska
- 1.6 81 km SE of King Cove, Alaska
- 1.6 Alaska Peninsula
- 2.0 79 km SE of King Cove, Alaska
- 2.7 73 km ESE of King Cove, Alaska
- 1.7 82 km SE of King Cove, Alaska
- 2.3 61 km ESE of King Cove, Alaska
- 2.2 81 km SE of King Cove, Alaska
- 1.7 87 km SSW of Sand Point, Alaska
Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of . QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.
On USGS
- The official USGS event page — the source of record for every value above
- Did you feel it? Report it to USGS — reports go to USGS, not to us
- ShakeMap for this event, when USGS has produced one
QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.