Earthquake · reviewed by a seismologist
M 1.6ml
62 km SSE of Adak, Alaska
Yes. A magnitude 1.6 earthquake was recorded 62 km SSE of Adak, Alaska at 14:15 UTC on 2018-07-18, 11 km deep.
- When
- Magnitude
- M 1.6 (ml)
- Depth
- 11 km below the surface
- Felt
- no reports yet
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1187 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 2 km (1 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 7.6 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 2,000,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,400,000× the energy of this one
- Around the size people start to feel M 3.0 130× the energy of this one
- This earthquake M 1.6 about 7.6 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 5.6 on 2017-04-04 — about 1,000,000 times the energy of this one.
Before 2016, the USGS record lists 138 earthquakes of M5 or more within 50 km; the five largest:
- 7.3 46 km SSW of Adak, Alaska · 39 km WNW of this epicentre
- 7.1 75 km S of Adak, Alaska · 33 km WSW of this epicentre
- 7.0 101 km S of Adak, Alaska · 41 km S of this epicentre
- 6.9 61 km SSW of Adak, Alaska · 36 km W of this epicentre
- 6.7 76 km SSE of Adak, Alaska · 15 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 51.3487, -176.3306. Map © OpenStreetMap contributors.
Aftershocks so far
57 earthquakes have been recorded within 50 km since this one.
- 2.6 106 km SSE of Adak, Alaska
- 2.7 86 km SSE of Adak, Alaska
- 3.2 102 km SSE of Adak, Alaska
- 2.7 101 km SSE of Adak, Alaska
- 3.3 110 km SSE of Adak, Alaska
- 3.3 35 km SE of Adak, Alaska
- 2.6 95 km SSE of Adak, Alaska
- 2.5 94 km SSE of Adak, Alaska
- 2.8 85 km SSE of Adak, Alaska
- 2.4 99 km SSE of Adak, Alaska
- 3.9 109 km SSE of Adak, Alaska
- 3.8 105 km SSE of Adak, Alaska
- 3.6 107 km SSE of Adak, Alaska
- 2.9 87 km SSE of Adak, Alaska
- 2.6 83 km SSE 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.