Earthquake · automatic estimate, may change
M 1.6ml
49 km ENE of Chenega, Alaska
Yes. A magnitude 1.6 earthquake was recorded 49 km ENE of Chenega, Alaska, at 10:41 pm AKDT on 20 September 2025 (06:41 UTC), 20 km deep. The magnitude and location are an automatic first estimate and may change.
- When
- Magnitude
- M 1.6 (ml)
- Depth
- 20 km below the surface
- Felt
- no reports yet
- Nearest
- Chugach Census Area, 61 km ENE
- Nearest mapped fault
- Patton Bay fault, 23 km from its surface trace — near is not the same as on
- Status
- Automatic — a machine’s first estimate, which may change
USGS · last changed by USGS · we first saw it 419 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 5.3 on 2017-11-27 — about 350,000 times the energy of this one.
Before 2016, the USGS record lists 16 earthquakes of M5 or more within 50 km; the five largest:
- 7.0 52 km NE of Chenega, Alaska · 11 km NNW of this epicentre
- 6.7 Prince William Sound, Alaska · 46 km NNE of this epicentre
- 6.4 Prince William Sound, Alaska · 19 km N of this epicentre
- 6.3 60 km SW of Cordova, Alaska · 32 km E of this epicentre
- 6.3 56 km WSW of Cordova, Alaska · 30 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 60.2756, -147.2298. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Chugach Census Area, AK | 61 km (38 mi) | ENE | earthquakes near Chugach Census Area |
| Anchorage Municipality, AK | 150 km (93 mi) | NW | earthquakes near Anchorage Municipality |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
54 earthquakes have been recorded within 50 km since this one.
- 1.7 43 km SW of Tatitlek, Alaska
- 2.0 37 km NNE of Chenega, Alaska
- 2.3 49 km WSW of Tatitlek, Alaska
- 2.1 51 km WSW of Tatitlek, Alaska
- 2.1 39 km NNE of Chenega, Alaska
- 1.5 46 km WSW of Tatitlek, Alaska
- 1.8 46 km WSW of Tatitlek, Alaska
- 1.7 54 km ESE of Whittier, Alaska
- 2.5 59 km ESE of Whittier, Alaska
- 2.4 37 km NNE of Chenega, Alaska
- 2.5 36 km NNE of Chenega, Alaska
- 2.0 52 km SW of Tatitlek, Alaska
- 2.4 49 km ENE of Chenega, Alaska
- 1.8 39 km SW of Tatitlek, Alaska
- 2.1 54 km NNE of Chenega, 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.