QuakeIndex

Earthquake · reviewed by a seismologist

M 2.0md

Earthquake near Mountain House, CA

No earthquake was likely felt in Mountain House in the 24 hours to 1:36 pm PST (21:36 UTC). The last one was M 3.5, 41 km (26 mi) S, at 7:21 am PDT on 27 September 2026, estimated intensity II (weak) in town; 8 felt reports to USGS. Every earthquake near Mountain House

This page: a magnitude 2.0 earthquake was recorded 12 km (8 mi) south-southwest of Mountain House, CA, at 7:40 am PST on 2 February 2018 (15:40 UTC), 12 km deep. 1 person has reported feeling it to USGS.

USGS: 12km SSW of Mountain House, CA

13 km (8 mi) E of Livermore, CA · 47 km (29 mi) NNE of San Jose, CA

7:40 am PST, Feb 2, 2018 · · 12 km deep · released about 31 lb of TNT

10 km30 km60 km120 km N Alameda County 27 kmContra Costa County 39 kmSan Joaquin County 41 kmSanta Clara County 52 kmStanislaus County 56 kmSolano County 70 kmSan Mateo County 73 kmSanta Cruz County 83 kmSacramento County 88 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
7:40 am PST on 2 February 2018 ()
Where
12 km (8 mi) south-southwest of Mountain House, CA · earthquakes near Mountain House
Magnitude
M 2.0 (md)
Depth
12 km below the surface
Felt
1 report · strongest reported intensity I
Nearest
Alameda County, 27 km W
Nearest mapped fault
Corral Hollow-Carnegie fault, 2 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 3198 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 11 km (7 mi) from the epicentre. In Mountain House, 12 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.

Earthquakes near other towns within 30 km: Livermore, Tracy, Byron, Pleasanton, Discovery Bay, Brentwood.

How big was it?

This earthquake released about 31 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.0 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 480,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 340,000× the energy of this one
  3. Around the size people start to feel M 3.0 31× the energy of this one
  4. This earthquake M 2.0 about 31 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 4.1 on 2017-10-10 — about 1,300 times the energy of this one.

Before 2016, the USGS record lists 8 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.2 Near San Jose, California · 46 km SSW of this epicentre
  2. 6.2 The 1984 Morgan Hill, California Earthquake · 42 km S of this epicentre
  3. 5.8 The 1980 Livermore, California Earthquake · 22 km NW of this epicentre
  4. 5.7 15 km NE of East Foothills, California · 24 km SSW of this epicentre
  5. 5.5 6 km NNE of East Foothills, California · 31 km SSW 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 37.6877, -121.6150. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Alameda County, CA 27 km (17 mi) W earthquakes near Alameda County
Contra Costa County, CA 39 km (24 mi) NW earthquakes near Contra Costa County
San Joaquin County, CA 41 km (25 mi) NE earthquakes near San Joaquin County
Santa Clara County, CA 52 km (32 mi) S earthquakes near Santa Clara County
Stanislaus County, CA 56 km (35 mi) ESE earthquakes near Stanislaus County
Solano County, CA 70 km (44 mi) NNW earthquakes near Solano County

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. 1.6 4km SW of Danville, CA
  2. 1.7 2km W of Diablo, CA
  3. 1.8 2km W of Diablo, CA
  4. 1.6 2km WSW of Diablo, CA
  5. 1.6 2km SW of Diablo, CA
  6. 1.9 2km ENE of Danville, CA
  7. 2.8 2km WSW of Diablo, CA
  8. 3.5 2km ENE of Danville, CA
  9. 3.4 2km ENE of Danville, CA
  10. 1.5 2km SW of Diablo, CA
  11. 1.6 2km E of Danville, CA
  12. 3.3 2km ENE of Danville, CA
  13. 1.6 1km WNW of Diablo, CA
  14. 1.9 2km WSW of Diablo, CA
  15. 2.8 2km WSW of Diablo, 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.