Earthquake · reviewed by a seismologist
M 1.5ml
Earthquake near Girdwood, AK
No earthquake was likely felt in Girdwood in the 24 hours to 12:06 am AKST (09:06 UTC). The last one was M 1.8, 8 km (5 mi) SE, at 10:01 am AKDT on 19 October 2026, estimated intensity II (weak) in town. Every earthquake near Girdwood
This page: a magnitude 1.5 earthquake was recorded 10 km (6 mi) southwest of Girdwood, AK, at 1:03 am AKDT on 21 September 2021 (09:03 UTC), 19 km deep.
USGS: 7 km ESE of Sunrise, Alaska
51 km (31 mi) SE of Anchorage, AK
- When
- 1:03 am AKDT on 21 September 2021 ()
- Where
- 10 km (6 mi) southwest of Girdwood, AK · earthquakes near Girdwood
- Magnitude
- M 1.5 (ml)
- Depth
- 19 km below the surface
- Felt
- no reports yet
- Nearest
- Anchorage Municipality, 34 km N
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1851 days ago
Earthquake alerts for Girdwood, AK
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Alerts are on for .
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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. In Girdwood, 10 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 5.4 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 2,800,000× the energy of this one
- Magna, Utah 2020 M 5.7 2,000,000× the energy of this one
- Around the size people start to feel M 3.0 180× the energy of this one
- This earthquake M 1.5 about 5.4 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 4.2 on 2020-06-18 — about 11,000 times the energy of this one.
Before 2016, the USGS record lists 9 earthquakes of M5 or more within 50 km; the five largest:
- 6.0 21 km N of Whittier, Alaska · 34 km ENE of this epicentre
- 5.7 13 km S of Girdwood, Alaska · 8 km SE of this epicentre
- 5.6 17 km W of Whittier, Alaska · 21 km SE of this epicentre
- 5.5 26 km SSW of Anchorage, Alaska · 47 km WNW of this epicentre
- 5.3 16 km WSW of Whittier, Alaska · 22 km SE 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 60.8719, -149.2910. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Anchorage Municipality, AK | 34 km (21 mi) | N | earthquakes near Anchorage Municipality |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
59 earthquakes have been recorded within 50 km since this one.
- 1.5 16 km SE of Elmendorf Air Force Base, Alaska
- 1.5 11 km NE of Girdwood, Alaska
- 2.9 18 km SSE of Girdwood, Alaska
- 1.9 6 km SE of Anchorage, Alaska
- 1.7 18 km NE of Moose Pass, Alaska
- 1.5 9 km SE of Anchorage, Alaska
- 2.1 18 km ESE of Elmendorf Air Force Base, Alaska
- 1.9 23 km WSW of Whittier, Alaska
- 2.8 10 km ESE of Eagle River, Alaska
- 1.8 1 km WSW of Girdwood, Alaska
- 1.7 20 km E of Crown Point, Alaska
- 2.7 13 km NNW of Hope, Alaska
- 3.5 15 km S of Hope, Alaska
- 1.5 14 km NNE of Cooper Landing, Alaska
- 1.7 13 km NNW of Girdwood, 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.