Earthquake · reviewed by a seismologist
M 2.2ml
237 km S of False Pass, Alaska
Yes. A magnitude 2.2 earthquake was recorded 237 km S of False Pass, Alaska at 15:34 UTC on 2021-04-18, 3.4 km deep.
- When
- Magnitude
- M 2.2 (ml)
- Depth
- 3.4 km below the surface
- Felt
- no reports yet
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 2012 days ago
This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.
At this magnitude and depth, people at rest would likely notice it out to about 18 km (11 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 60 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.2 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 250,000× the energy of this one
- Magna, Utah 2020 M 5.7 180,000× the energy of this one
- Around the size people start to feel M 3.0 16× the energy of this one
- This earthquake M 2.2 about 60 lb of TNT
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 2016-10-01 — about 16,000 times the energy of this one.
Before 2016, the USGS record lists 4 earthquakes of M5 or more within 50 km:
- 5.9 228 km S of False Pass, Alaska · 26 km WNW of this epicentre
- 5.6 203 km SSE of False Pass, Alaska · 39 km NNE of this epicentre
- 5.3 223 km S of False Pass, Alaska · 18 km NW of this epicentre
- 5.0 240 km SSE of False Pass, Alaska · 34 km E 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 52.7605, -162.6953. Map © OpenStreetMap contributors.
Aftershocks so far
57 earthquakes have been recorded within 50 km since this one.
- 2.9 245 km S of False Pass, Alaska
- 2.7 233 km SSE of False Pass, Alaska
- 2.9 215 km SSE of False Pass, Alaska
- 2.9 214 km SSE of False Pass, Alaska
- 2.8 229 km SSE of False Pass, Alaska
- 2.7 218 km SSE of False Pass, Alaska
- 3.3 269 km S of False Pass, Alaska
- 2.9 215 km S of False Pass, Alaska
- 3.4 262 km SE of Akutan, Alaska
- 2.8 212 km SSE of False Pass, Alaska
- 3.2 245 km S of False Pass, Alaska
- 3.3 244 km SE of Akutan, Alaska
- 2.6 228 km SSE of False Pass, Alaska
- 3.1 248 km S of False Pass, Alaska
- 2.7 238 km SSE 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.
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.