Earthquake · reviewed by a seismologist
M 1.9ml
21 km SW of Nanwalek, Alaska
Yes. A magnitude 1.9 earthquake was recorded 21 km SW of Nanwalek, Alaska, at 8:25 pm AKST on 20 February 2019 (05:25 UTC), 55 km deep.
- When
- Magnitude
- M 1.9 (ml)
- Depth
- 55 km below the surface
- Felt
- no reports yet
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 2804 days ago
Earthquake alerts for Homer, AK
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Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
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 21 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 710,000× the energy of this one
- Magna, Utah 2020 M 5.7 500,000× the energy of this one
- Around the size people start to feel M 3.0 45× the energy of this one
- This earthquake M 1.9 about 21 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 2017-03-02 — about 350,000 times the energy of this one.
Before 2016, the USGS record lists 13 earthquakes of M5 or more within 50 km; the five largest:
- 6.4 25 km NW of Nanwalek, Alaska · 28 km N of this epicentre
- 6.0 61 km WSW of Nanwalek, Alaska · 41 km WSW of this epicentre
- 5.9 Southern Alaska · 42 km WNW of this epicentre
- 5.8 63 km WSW of Nanwalek, Alaska · 42 km WSW of this epicentre
- 5.5 6 km WNW of Nanwalek, Alaska · 18 km NE 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 59.2441, -152.2333. Map © OpenStreetMap contributors.
Aftershocks so far
55 earthquakes have been recorded within 50 km since this one.
- 1.6 48 km SSW of Nanwalek, Alaska
- 2.1 59 km SSW of Nanwalek, Alaska
- 2.1 59 km SSW of Nanwalek, Alaska
- 3.0 61 km SSW of Nanwalek, Alaska
- 5.8 61 km SSW of Nanwalek, Alaska
- 1.7 33 km NW of Nanwalek, Alaska
- 1.6 26 km WNW of Nanwalek, Alaska
- 1.5 33 km WSW of Nanwalek, Alaska
- 2.4 7 km W of Seldovia, Alaska
- 1.6 19 km NW of Nanwalek, Alaska
- 1.5 50 km SW of Nanwalek, Alaska
- 1.5 48 km W of Nanwalek, Alaska
- 2.0 45 km WSW of Anchor Point, Alaska
- 1.6 40 km SW of Nanwalek, Alaska
- 1.5 29 km WSW of Anchor Point, 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.