explosion · reviewed by a seismologist
M 2.3ml
Earthquake near Altamont, OR
USGS: 5 km W of Merrill, Oregon
- When
- 9:46 am PST on 17 February 2021 ()
- Where
- 20 km (13 mi) SSE of Altamont, OR · earthquakes near Altamont
- Magnitude
- M 2.3 (ml)
- Depth
- -1.3 km below the surface
- Felt
- no reports yet
- Nearest
- Klamath County, 73 km N
- Nearest mapped fault
- Klamath graben fault system, 1 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 2053 days ago
A magnitude 2.3 earthquake was recorded 20 km (13 mi) SSE of Altamont, OR, at 9:46 am PST on 17 February 2021 (17:46 UTC). This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.
Earthquakes near other towns within 30 km: Klamath Falls.
USGS catalogues this as explosion, not an earthquake.
How big was it?
This earthquake released about 74 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.3 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 200,000× the energy of this one
- Magna, Utah 2020 M 5.7 140,000× the energy of this one
- Around the size people start to feel M 3.0 13× the energy of this one
- This earthquake M 2.3 about 74 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
No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.
Before 2016, the USGS record lists 3 earthquakes of M5 or more within 50 km:
- 6.0 27 km WNW of Klamath Falls, Oregon · 48 km NW of this epicentre
- 5.9 22 km WNW of Klamath Falls, Oregon · 43 km NW of this epicentre
- 5.1 20 km WNW of Klamath Falls, Oregon · 40 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 42.0305, -121.6712. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Klamath County, OR | 73 km (45 mi) | N | earthquakes near Klamath County |
| Siskiyou County, CA | 87 km (54 mi) | SW | earthquakes near Siskiyou County |
| Modoc County, CA | 93 km (58 mi) | ESE | earthquakes near Modoc County |
| Jackson County, OR | 93 km (58 mi) | WNW | earthquakes near Jackson County |
| Lake County, OR | 135 km (84 mi) | NE | earthquakes near Lake County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
42 earthquakes have been recorded within 50 km since this one.
- 1.0 18 km WNW of Klamath Falls, Oregon
- 1.9 10 km NNW of Klamath Falls, Oregon
- 2.1 5 km SSW of Merrill, Oregon
- 1.8 31 km E of Tennant, CA
- 2.0 11 km NNW of Klamath Falls, Oregon
- 2.7 10 km E of Bonanza, Oregon
- 1.6 11 km NNW of Klamath Falls, Oregon
- 2.2 5 km W of Merrill, Oregon
- 1.6 23 km WSW of Klamath Falls, Oregon
- 1.6 25 km WNW of Klamath Falls, Oregon
- 1.8 16 km ESE of Dorris, California
- 2.5 6 km NW of Macdoel, CA
- 1.7 10 km NNW of Klamath Falls, Oregon
- 1.7 26 km WNW of Klamath Falls, Oregon
- 1.6 10 km WSW of Klamath Falls, Oregon
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.