Earthquake · reviewed by a seismologist
M 4.8mw
Earthquake near Anchorage, AK
No earthquake was likely felt in Anchorage in the 24 hours to 2:14 pm AKST (23:14 UTC). The last one was M 3.5, 39 km (24 mi) SSW, at 4:48 pm AKDT on 27 October 2026, estimated intensity II (weak) in town; 98 felt reports to USGS. Every earthquake near Anchorage
This page: a magnitude 4.8 earthquake was recorded 14 km (9 mi) north-northwest of Anchorage, AK, at 12:45 pm AKST on 6 December 2018 (21:45 UTC), 43 km deep. 556 people have reported feeling it to USGS.
USGS: 2 km SSE of Point MacKenzie, Alaska
14 km (9 mi) NNW of Anchorage, AK
- When
- 12:45 pm AKST on 6 December 2018 ()
- Where
- 14 km (9 mi) north-northwest of Anchorage, AK · earthquakes near Anchorage
- Magnitude
- M 4.8 (mw)
- Depth
- 43 km below the surface
- Felt
- 556 reports · strongest reported intensity IV
- Measured shaking
- intensity IV (ShakeMap)
- USGS impact alert
- green
- Tsunami
- USGS flagged this event for tsunami evaluation. Follow tsunami.gov for official messages.
- Nearest
- Anchorage Municipality, 40 km ESE
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1184 days ago
Earthquake alerts for Anchorage, 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 light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.
At this magnitude and depth, people at rest would likely notice it out to about 165 km (103 mi) from the epicentre. In Anchorage, 14 km away, the estimate is intensity III (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.
Likely felt in: Anchorage 14 km, intensity III · Big Lake 20 km, intensity III · Eagle River 21 km, intensity III · Knik-Fairview 27 km, intensity III · Tanaina 42 km, intensity III · Willow 45 km, intensity III. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 240 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.8 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 710× the energy of this one
- Mineral, Virginia 2011 M 5.8 32× the energy of this one
- Magna, Utah 2020 M 5.7 22× the energy of this one
- This earthquake M 4.8 about 240 tons of TNT
- Around the size people start to feel M 3.0 this one released 500× more
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 7.1 on 2018-11-30 — about 2,800 times the energy of this one.
Before 2016, the USGS record lists 22 earthquakes of M5 or more within 50 km; the five largest:
- 5.8 20 km ENE of Beluga, Alaska · 45 km WSW of this epicentre
- 5.6 11 km NW of Big Lake, Alaska · 28 km NNW of this epicentre
- 5.6 5 km N of Susitna, Alaska · 41 km NW of this epicentre
- 5.5 2 km ENE of Eagle River, Alaska · 23 km E of this epicentre
- 5.5 9 km E of Susitna, Alaska · 30 km NW 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 61.3407, -149.9550. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Anchorage Municipality, AK | 40 km (25 mi) | ESE | earthquakes near Anchorage Municipality |
| Matanuska-Susitna Borough, AK | 106 km (66 mi) | NNE | earthquakes near Matanuska-Susitna Borough |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
60 earthquakes have been recorded within 50 km since this one.
- 1.7 5 km WSW of Point MacKenzie, Alaska
- 2.1 5 km WNW of Point MacKenzie, Alaska
- 2.5 8 km W of Knik, Alaska
- 2.8 2 km WSW of Point MacKenzie, Alaska
- 1.7 8 km NNE of Point MacKenzie, Alaska
- 1.9 8 km SSE of Big Lake, Alaska
- 1.6 3 km SSE of Big Lake, Alaska
- 1.6 3 km SW of Point MacKenzie, Alaska
- 1.6 7 km NW of Point MacKenzie, Alaska
- 2.3 6 km WNW of Point MacKenzie, Alaska
- 2.3 5 km NNW of Anchorage, Alaska
- 2.9 4 km NW of Point MacKenzie, Alaska
- 2.4 7 km N of Anchorage, Alaska
- 1.6 2 km WSW of Point MacKenzie, Alaska
- 2.1 7 km NNE of Point MacKenzie, 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.