Earthquake · reviewed by a seismologist
M 4.0mwr
158 km S of False Pass, Alaska
- When
- Magnitude
- M 4.0 (mwr)
- Depth
- 35 km below the surface
- Felt
- no reports yet
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 716 days ago
This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.
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.
Where
Epicentre 53.4320, -163.6328. Map © OpenStreetMap contributors.
Aftershocks so far
52 earthquakes have been recorded within 50 km since this one.
- 2.6 156 km S of False Pass, Alaska
- 2.7 125 km S of False Pass, Alaska
- 4.0 141 km S of False Pass, Alaska
- 3.3 151 km S of False Pass, Alaska
- 2.7 129 km ESE of Akutan, Alaska
- 2.5 120 km ESE of Akutan, Alaska
- 3.0 121 km ESE of Akutan, Alaska
- 3.4 119 km ESE of Akutan, Alaska
- 2.8 126 km SSW of False Pass, Alaska
- 2.6 138 km ESE of Akutan, Alaska
- 2.2 146 km S of False Pass, Alaska
- 2.2 113 km SSW of False Pass, Alaska
- 2.7 146 km S of False Pass, Alaska
- 2.7 161 km S of False Pass, Alaska
- 2.7 155 km S of False Pass, 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.
For this area
The largest earthquake within 50 km in our catalogue was M 5.9 on 2016-10-27 — it released about 710 times the energy of this one.
From the QuakeIndex catalogue, built from the USGS FDSN event service.
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.