Earthquake · reviewed by a seismologist
M 3.3ml
155 km SSW of Adak, Alaska
Yes. A magnitude 3.3 earthquake was recorded 155 km SSW of Adak, Alaska at 22:45 UTC on 2019-04-02, 10 km deep.
- When
- Magnitude
- M 3.3 (ml)
- Depth
- 10 km below the surface
- Felt
- no reports yet
- Nearest mapped fault
- Alaska-Aleutian subduction zone, 19 km from its surface trace — near is not the same as on
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 2706 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 51 km (32 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 1.3 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.3 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 130,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 5,600× the energy of this one
- Magna, Utah 2020 M 5.7 4,000× the energy of this one
- This earthquake M 3.3 about 1.3 tons of TNT
- Around the size people start to feel M 3.0 this one released 2.8× 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 4.3 on 2018-03-11 — about 32 times the energy of this one.
Before 2016, the USGS record lists 18 earthquakes of M5 or more within 50 km; the five largest:
- 6.5 184 km SSW of Adak, Alaska · 28 km SSW of this epicentre
- 6.4 146 km S of Adak, Alaska · 44 km E of this epicentre
- 6.0 130 km SSW of Adak, Alaska · 28 km N of this epicentre
- 6.0 161 km SSW of Adak, Alaska · 8 km WSW of this epicentre
- 6.0 136 km S of Adak, Alaska · 36 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 50.5709, -177.4522. Map © OpenStreetMap contributors.
Aftershocks so far
45 earthquakes have been recorded within 50 km since this one.
- 2.4 179 km SSW of Adak, Alaska
- 3.7 164 km SSW of Adak, Alaska
- 1.8 120 km SW of Adak, Alaska
- 3.1 178 km SSW of Adak, Alaska
- 3.3 188 km SSW of Adak, Alaska
- 2.1 130 km SW of Adak, Alaska
- 2.3 178 km S of Adak, Alaska
- 3.2 118 km SSW of Adak, Alaska
- 1.8 Andreanof Islands, Aleutian Islands, Alaska
- 2.3 179 km SSW of Adak, Alaska
- 3.9 177 km SSW of Adak, Alaska
- 2.0 183 km S of Adak, Alaska
- 2.1 186 km SSW of Adak, Alaska
- 1.5 137 km SSW of Adak, Alaska
- 2.5 168 km SSW of Adak, 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.