Earthquake · reviewed by a seismologist
M 1.6ml
99 km SSW of False Pass, Alaska
Yes. A magnitude 1.6 earthquake was recorded 99 km SSW of False Pass, Alaska at 12:41 UTC on 2018-09-11, 26 km deep.
- When
- Magnitude
- M 1.6 (ml)
- Depth
- 26 km below the surface
- Felt
- no reports yet
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 2538 days ago
This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.
At this magnitude and depth it was probably too small to be felt, even directly above it. 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 5.1 on 2016-10-27 — about 180,000 times the energy of this one.
Before 2016, the USGS record lists 52 earthquakes of M5 or more within 50 km; the five largest:
- 6.6 146 km ESE of Akutan, Alaska · 49 km S of this epicentre
- 6.5 79 km SW of False Pass, Alaska · 43 km NW of this epicentre
- 6.2 Unimak Island region, Alaska · 26 km SSW of this epicentre
- 6.2 102 km SSW of False Pass, Alaska · 16 km W of this epicentre
- 6.2 136 km S of False Pass, Alaska · 37 km S 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 53.9810, -163.7587. Map © OpenStreetMap contributors.
Aftershocks so far
59 earthquakes have been recorded within 50 km since this one.
- 2.6 104 km SSW of False Pass, Alaska
- 3.5 Unimak Island region, Alaska
- 2.4 140 km ESE of Akutan, Alaska
- 2.3 125 km ESE of Akutan, Alaska
- 2.3 121 km ESE of Akutan, Alaska
- 2.1 112 km SSW of False Pass, Alaska
- 3.7 112 km SSW of False Pass, Alaska
- 2.4 107 km ESE of Akutan, Alaska
- 2.5 114 km ESE of Akutan, Alaska
- 2.3 110 km ESE of Akutan, Alaska
- 1.8 91 km SSW of False Pass, Alaska
- 2.0 77 km SSW of False Pass, Alaska
- 2.4 87 km SW of False Pass, Alaska
- 2.0 89 km S of False Pass, Alaska
- 2.2 74 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.
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.