QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6ml

Earthquake near Altamont, OR

USGS: 11 km SSE of Bonanza, Oregon

5:06 am PDT, May 18, 2021 · · 14 km deep · released about 7.1 lb of TNT

Every earthquake near Altamont Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Klamath County 69 kmModoc County 77 kmLake County 108 kmSiskiyou County 115 kmJackson County 116 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
5:06 am PDT on 18 May 2021 ()
Where
35 km (22 mi) ESE of Altamont, OR · earthquakes near Altamont
Magnitude
M 1.6 (ml)
Depth
14 km below the surface
Felt
no reports yet
Nearest
Klamath County, 69 km NNW
Nearest mapped fault
Klamath graben fault system, 18 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 1963 days ago

A magnitude 1.6 earthquake was recorded 35 km (22 mi) ESE of Altamont, OR, at 5:06 am PDT on 18 May 2021 (12:06 UTC). This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

How big was it?

This earthquake released about 7.1 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,100,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,500,000× the energy of this one
  3. Around the size people start to feel M 3.0 130× the energy of this one
  4. This earthquake M 1.6 about 7.1 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 since 1900 lists no earthquake of M5 or more within 50 km.

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 42.1107, -121.3322. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Klamath County, OR 69 km (43 mi) NNW earthquakes near Klamath County
Modoc County, CA 77 km (48 mi) SE earthquakes near Modoc County
Lake County, OR 108 km (67 mi) NE earthquakes near Lake County
Siskiyou County, CA 115 km (72 mi) WSW earthquakes near Siskiyou County
Jackson County, OR 116 km (72 mi) WNW earthquakes near Jackson County

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

36 earthquakes have been recorded within 50 km since this one.

  1. 1.9 10 km NNW of Klamath Falls, Oregon
  2. 2.1 5 km SSW of Merrill, Oregon
  3. 2.0 11 km NNW of Klamath Falls, Oregon
  4. 1.6 36 km E of Bonanza, Oregon
  5. 2.7 10 km E of Bonanza, Oregon
  6. 1.7 36 km E of Bonanza, Oregon
  7. 1.6 11 km NNW of Klamath Falls, Oregon
  8. 2.3 36 km E of Bonanza, Oregon
  9. 1.8 37 km E of Bonanza, Oregon
  10. 2.1 36 km E of Bonanza, Oregon
  11. 2.2 5 km W of Merrill, Oregon
  12. 2.2 36 km E of Bonanza, Oregon
  13. 1.7 36 km E of Bonanza, Oregon
  14. 1.8 36 km E of Bonanza, Oregon
  15. 1.6 34 km E of Bonanza, 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

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.