Earthquake · reviewed by a seismologist
M 4.0mb
155 km ESE of Atka, Alaska
Yes. A magnitude 4.0 earthquake was recorded 155 km ESE of Atka, Alaska at 02:15 UTC on 2024-09-03, 35 km deep.
- When
- Magnitude
- M 4.0 (mb)
- Depth
- 35 km below the surface
- Felt
- no reports yet
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 729 days ago
This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.
At this magnitude and depth, people at rest would likely notice it out to about 90 km (56 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 15 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.0 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 11,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 500× the energy of this one
- Magna, Utah 2020 M 5.7 350× the energy of this one
- This earthquake M 4.0 about 15 tons of TNT
- Around the size people start to feel M 3.0 this one released 32× 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 since 2016 was M 5.0 on 2023-11-03 — about 32 times the energy of this one.
Before 2016, the USGS record lists 24 earthquakes of M5 or more within 50 km; the five largest:
- 7.3 Fox Islands, Aleutian Islands, Alaska · 33 km NNE of this epicentre
- 6.9 170 km E of Atka, Alaska · 49 km NNE of this epicentre
- 6.5 143 km ESE of Atka, Alaska · 15 km WSW of this epicentre
- 6.3 143 km E of Atka, Alaska · 26 km NNW of this epicentre
- 6.1 185 km ESE of Atka, Alaska · 34 km ENE of this epicentre
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 51.7845, -172.0398. Map © OpenStreetMap contributors.
Aftershocks so far
52 earthquakes have been recorded within 50 km since this one.
- 3.0 117 km ESE of Atka, Alaska
- 3.2 178 km E of Atka, Alaska
- 2.9 119 km ESE of Atka, Alaska
- 3.1 118 km ESE of Atka, Alaska
- 3.6 130 km E of Atka, Alaska
- 2.6 150 km E of Atka, Alaska
- 2.9 179 km ESE of Atka, Alaska
- 3.3 136 km ESE of Atka, Alaska
- 2.8 184 km E of Atka, Alaska
- 3.8 138 km E of Atka, Alaska
- 2.9 175 km E of Atka, Alaska
- 3.2 114 km ESE of Atka, Alaska
- 3.2 116 km E of Atka, Alaska
- 3.4 182 km E of Atka, Alaska
- 3.2 130 km ESE of Atka, 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.