Earthquake · reviewed by a seismologist
M 1.8ml
54 km NNW of Chickaloon, Alaska
Yes. A magnitude 1.8 earthquake was recorded 54 km NNW of Chickaloon, Alaska, at 3:31 pm AKDT on 4 July 2018 (23:31 UTC), 11 km deep.
- When
- Magnitude
- M 1.8 (ml)
- Depth
- 11 km below the surface
- Felt
- no reports yet
- Nearest
- Matanuska-Susitna Borough, 39 km W
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1185 days ago
Earthquake alerts for Susitna North, 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, people at rest would likely notice it out to about 8 km (5 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 15 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 1,000,000× the energy of this one
- Magna, Utah 2020 M 5.7 710,000× the energy of this one
- Around the size people start to feel M 3.0 63× the energy of this one
- This earthquake M 1.8 about 15 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 4.3 on 2018-02-28 — about 5,600 times the energy of this one.
Before 2016, the USGS record lists 6 earthquakes of M5 or more within 50 km; the five largest:
- 5.8 37 km ENE of Susitna North, Alaska · 24 km W of this epicentre
- 5.8 14 km NNE of Fishhook, Alaska · 50 km SSW of this epicentre
- 5.3 55 km NNE of Chickaloon, Alaska · 31 km E of this epicentre
- 5.1 25 km ENE of Susitna North, Alaska · 34 km W of this epicentre
- 5.0 70 km ENE of Chase, Alaska · 49 km N 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 62.2693, -148.7425. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Matanuska-Susitna Borough, AK | 39 km (24 mi) | W | earthquakes near Matanuska-Susitna Borough |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
53 earthquakes have been recorded within 50 km since this one.
- 2.8 Central Alaska
- 1.6 44 km ENE of Susitna North, Alaska
- 2.5 32 km ESE of Susitna North, Alaska
- 2.4 19 km NNW of Chickaloon, Alaska
- 1.5 61 km N of Chickaloon, Alaska
- 2.7 35 km ENE of Susitna North, Alaska
- 1.8 29 km N of Chickaloon, Alaska
- 1.5 64 km ENE of Chase, Alaska
- 1.7 17 km N of Fishhook, Alaska
- 1.6 69 km N of Chickaloon, Alaska
- 1.7 49 km E of Chase, Alaska
- 2.1 48 km NNW of Chickaloon, Alaska
- 1.5 50 km ENE of Susitna North, Alaska
- 1.9 20 km NNE of Chickaloon, Alaska
- 1.6 44 km NE of Susitna North, 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.