Earthquake · reviewed by a seismologist
M 3.4ml
158 km E of Atka, Alaska
Yes. A magnitude 3.4 earthquake was recorded 158 km E of Atka, Alaska at 01:23 UTC on 2026-02-18, 10 km deep.
- When
- Magnitude
- M 3.4 (ml)
- Depth
- 10 km below the surface
- Felt
- no reports yet
- Measured shaking
- intensity II (ShakeMap)
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 127 days ago
This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.
At this magnitude and depth, people at rest would likely notice it out to about 57 km (35 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 1.9 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.4 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 89,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 4,000× the energy of this one
- Magna, Utah 2020 M 5.7 2,800× the energy of this one
- This earthquake M 3.4 about 1.9 tons of TNT
- Around the size people start to feel M 3.0 this one released 4× 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 250 times the energy of this one.
Before 2016, the USGS record lists 38 earthquakes of M5 or more within 50 km; the five largest:
- 7.3 Fox Islands, Aleutian Islands, Alaska · 4 km E of this epicentre
- 6.9 170 km E of Atka, Alaska · 18 km NE of this epicentre
- 6.5 143 km ESE of Atka, Alaska · 41 km SW of this epicentre
- 6.3 143 km E of Atka, Alaska · 17 km WSW of this epicentre
- 6.1 185 km ESE of Atka, Alaska · 32 km SE 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 52.0545, -171.8951. Map © OpenStreetMap contributors.
Aftershocks so far
39 earthquakes have been recorded within 50 km since this one.
- 3.2 178 km E of Atka, Alaska
- 3.6 130 km E of Atka, Alaska
- 2.6 150 km E of Atka, Alaska
- 2.9 178 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
- 2.8 188 km E of Atka, Alaska
- 3.8 138 km E of Atka, Alaska
- 2.9 175 km E of Atka, Alaska
- 3.1 173 km E of Atka, Alaska
- 2.5 176 km E of Atka, Alaska
- 2.7 188 km E of Atka, Alaska
- 2.9 176 km E of Atka, Alaska
- 2.7 172 km E 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.