Earthquake · reviewed by a seismologist
M 2.7ml
Earthquake near Nikiski, AK
No earthquake was likely felt in Nikiski in the 24 hours to 11:38 pm AKST (08:38 UTC). The last one was M 4.3, 58 km (36 mi) SSE, at 2:30 am AKST on 1 November 2026, estimated intensity II (weak) in town; 115 felt reports to USGS. Every earthquake near Nikiski
This page: a magnitude 2.7 earthquake was recorded 35 km (22 mi) northwest of Nikiski, AK, at 10:10 am AKDT on 21 October 2018 (18:10 UTC), 75 km deep.
USGS: 32 km WSW of Tyonek, Alaska
- When
- 10:10 am AKDT on 21 October 2018 ()
- Where
- 35 km (22 mi) northwest of Nikiski, AK · earthquakes near Nikiski
- Magnitude
- M 2.7 (ml)
- Depth
- 75 km below the surface
- Felt
- no reports yet
- Nearest
- Kenai Peninsula Borough, 73 km SSW
- Nearest mapped fault
- Middle Ground Shoal anticline (Cook Inlet folds), 15 km from its surface trace — near is not the same as on
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1185 days ago
Earthquake alerts for Nikiski, 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 small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.
At this magnitude and depth it was probably too small to be felt, even directly above it. In Nikiski, 35 km away, the estimate is intensity II (weak). 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 340 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.7 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 45,000× the energy of this one
- Magna, Utah 2020 M 5.7 32,000× the energy of this one
- Around the size people start to feel M 3.0 2.8× the energy of this one
- This earthquake M 2.7 about 340 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 5.2 on 2017-05-30 — about 5,600 times the energy of this one.
Before 2016, the USGS record lists 15 earthquakes of M5 or more within 50 km; the five largest:
- 6.8 Southern Alaska · 35 km ENE of this epicentre
- 6.8 4 km NE of Beluga, Alaska · 44 km NE of this epicentre
- 6.7 6 km WNW of Nikiski, Alaska · 30 km SSE of this epicentre
- 6.4 19 km SSE of Tyonek, Alaska · 35 km E of this epicentre
- 6.0 Southern Alaska · 31 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 60.9416, -151.6884. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Kenai Peninsula Borough, AK | 73 km (45 mi) | SSW | earthquakes near Kenai Peninsula Borough |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
56 earthquakes have been recorded within 50 km since this one.
- 1.5 18 km WNW of Tyonek, Alaska
- 1.9 41 km NW of Beluga, Alaska
- 1.9 20 km WNW of Tyonek, Alaska
- 1.6 4 km SSE of Nikiski, Alaska
- 1.6 26 km WNW of Tyonek, Alaska
- 1.5 27 km W of Salamatof, Alaska
- 1.6 26 km WNW of Salamatof, Alaska
- 1.5 23 km NNW of Nikiski, Alaska
- 1.6 22 km W of Salamatof, Alaska
- 1.7 31 km WNW of Tyonek, Alaska
- 1.7 37 km WNW of Nikiski, Alaska
- 1.5 64 km WNW of Beluga, Alaska
- 1.7 29 km W of Salamatof, Alaska
- 1.7 25 km NW of Beluga, Alaska
- 1.9 19 km WNW of Salamatof, 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.