QuakeIndex

Earthquake · reviewed by a seismologist

M 2.4md

Earthquake near Rancho Tehama Reserve, CA

No earthquake was likely felt in Rancho Tehama Reserve in the 24 hours to 9:00 am PST (17:00 UTC). The last one was M 4.0, 74 km (46 mi) SW, at 5:01 am PDT on 28 October 2026, estimated intensity II (weak) in town; 14 felt reports to USGS. Every earthquake near Rancho Tehama Reserve

This page: a magnitude 2.4 earthquake was recorded 43 km (27 mi) west of Rancho Tehama Reserve, CA, at 5:08 am PST on 24 February 2018 (13:08 UTC), 3.5 km deep. 1 person has reported feeling it to USGS.

USGS: 41km NE of Covelo, CA

98 km (61 mi) WNW of Chico, CA

5:08 am PST, Feb 24, 2018 · · 3.5 km deep · released about 100 lb of TNT

10 km30 km60 km120 km N Tehama County 58 kmGlenn County 65 kmTrinity County 69 kmMendocino County 82 kmLake County 105 kmShasta County 108 kmColusa County 112 kmHumboldt County 114 kmButte County 119 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
5:08 am PST on 24 February 2018 ()
Where
43 km (27 mi) west of Rancho Tehama Reserve, CA · earthquakes near Rancho Tehama Reserve
Magnitude
M 2.4 (md)
Depth
3.5 km below the surface
Felt
1 report · strongest reported intensity II
Nearest
Tehama County, 58 km E
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3178 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 20 km (12 mi) from the epicentre. In Rancho Tehama Reserve, 43 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 100 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.4 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 150,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 110,000× the energy of this one
  3. Around the size people start to feel M 3.0 9.4× the energy of this one
  4. This earthquake M 2.4 about 100 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 one earthquake of M5 or more within 50 km:

  1. 5.5 33 km NW of Rancho Tehama Reserve, California · 23 km NE 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 40.0452, -122.9003. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Tehama County, CA 58 km (36 mi) E earthquakes near Tehama County
Glenn County, CA 65 km (40 mi) SE earthquakes near Glenn County
Trinity County, CA 69 km (43 mi) NNW earthquakes near Trinity County
Mendocino County, CA 82 km (51 mi) SW earthquakes near Mendocino County
Lake County, CA 105 km (65 mi) S earthquakes near Lake County
Shasta County, CA 108 km (67 mi) NE earthquakes near Shasta County

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

Aftershocks so far

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

  1. 1.8 15km NW of Alder Springs, CA
  2. 2.5 20km NNW of Alder Springs, CA
  3. 1.6 20km NNW of Alder Springs, CA
  4. 2.1 20km NNW of Alder Springs, CA
  5. 1.8 19km SSE of Hayfork, CA
  6. 1.9 36km SSE of Hayfork, CA
  7. 1.6 18km NNW of Covelo, CA
  8. 1.6 25km W of Rancho Tehama Reserve, CA
  9. 2.3 17km ESE of Hayfork, CA
  10. 1.8 37km NNW of Alder Springs, CA
  11. 1.7 5km WNW of Covelo, CA
  12. 1.7 15km N of Alder Springs, CA
  13. 2.0 44km NNE of Covelo, CA
  14. 2.0 38km S of Hayfork, CA
  15. 2.1 38km S of Hayfork, CA

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.