Earthquake · reviewed by a seismologist
M 4.3mb
86 km SSE of Sand Point, Alaska
Yes. A magnitude 4.3 earthquake was recorded 86 km SSE of Sand Point, Alaska, at 2:40 am AKDT on 23 July 2020 (10:40 UTC), 35 km deep.
- When
- Magnitude
- M 4.3 (mb)
- Depth
- 35 km below the surface
- Felt
- no reports yet
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 2232 days ago
Earthquake alerts for Sand Point, AK
Get a notification in this browser when USGS records an earthquake near Sand Point, AK. No account or email needed.
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 116 km (72 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 43 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.3 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 4,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 180× the energy of this one
- Magna, Utah 2020 M 5.7 130× the energy of this one
- This earthquake M 4.3 about 43 tons of TNT
- Around the size people start to feel M 3.0 this one released 89× 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 4.7 on 2019-09-03 — about 4 times the energy of this one.
Before 2016, the USGS record lists 23 earthquakes of M5 or more within 50 km; the five largest:
- 7.4 54 km SE of Sand Point, Alaska · 35 km NNW of this epicentre
- 6.6 72 km SE of Sand Point, Alaska · 29 km NNE of this epicentre
- 6.6 85 km SE of Sand Point, Alaska · 13 km NE of this epicentre
- 6.5 94 km ESE of Sand Point, Alaska · 46 km NE of this epicentre
- 6.3 68 km SE of Sand Point, Alaska · 33 km NNE 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 54.6838, -159.7627. Map © OpenStreetMap contributors.
Aftershocks so far
54 earthquakes have been recorded within 50 km since this one.
- 1.7 59 km SE of Sand Point, Alaska
- 1.8 79 km SSE of Sand Point, Alaska
- 1.6 56 km SSE of Sand Point, Alaska
- 1.7 52 km SSE of Sand Point, Alaska
- 1.7 56 km SSE of Sand Point, Alaska
- 1.9 83 km SE of Sand Point, Alaska
- 1.7 53 km SSE of Sand Point, Alaska
- 1.7 57 km SSE of Sand Point, Alaska
- 2.1 59 km SSE of Sand Point, Alaska
- 1.7 52 km SSE of Sand Point, Alaska
- 1.6 57 km SSE of Sand Point, Alaska
- 1.8 68 km SSE of Sand Point, Alaska
- 1.9 81 km ESE of Sand Point, Alaska
- 2.3 73 km SSE of Sand Point, Alaska
- 1.9 68 km SE of Sand Point, 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.