QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6md

Earthquake near Mountain House, CA

No earthquake was likely felt in Mountain House in the 24 hours to 5:42 am PST (13:42 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 1.6 earthquake was recorded 6 km (4 mi) west-northwest of Mountain House, CA, at 2:57 pm PST on 8 November 2018 (22:57 UTC), 12 km deep.

USGS: 6km WNW of Mountain House, CA

58 km (36 mi) NNE of San Jose, CA · 16 km (10 mi) WNW of Tracy, CA

2:57 pm PST, Nov 8, 2018 · · 12 km deep · released about 8.1 lb of TNT

Every earthquake near Mountain House Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Alameda County 31 kmContra Costa County 33 kmSan Joaquin County 34 kmStanislaus County 60 kmSolano County 60 kmSanta Clara County 64 kmSacramento County 77 kmSan Mateo County 79 kmSanta Cruz County 94 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
2:57 pm PST on 8 November 2018 ()
Where
6 km (4 mi) west-northwest of Mountain House, CA · earthquakes near Mountain House
Magnitude
M 1.6 (md)
Depth
12 km below the surface
Felt
no reports yet
Nearest
Alameda County, 31 km WSW
Nearest mapped fault
Corral Hollow-Carnegie fault, 12 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 2927 days ago

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

At this magnitude and depth it was probably too small to be felt, even directly above it. In Mountain House, 6 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: Byron, Discovery Bay, Brentwood, Tracy, Livermore, Knightsen.

How big was it?

This earthquake released about 8.1 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 1,900,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,300,000× the energy of this one
  3. Around the size people start to feel M 3.0 120× the energy of this one
  4. This earthquake M 1.6 about 8.1 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 lists 6 earthquakes of M5 or more within 50 km; the five largest:

  1. 5.8 The 1980 Livermore, California Earthquake · 14 km WNW of this epicentre
  2. 5.7 15 km NE of East Foothills, California · 36 km S of this epicentre
  3. 5.5 6 km NNE of East Foothills, California · 42 km SSW of this epicentre
  4. 5.4 9 km NE of Livermore, California · 10 km WSW of this epicentre
  5. 5.3 6 km E of East Foothills, California · 46 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 37.7945, -121.6140. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Alameda County, CA 31 km (19 mi) WSW earthquakes near Alameda County
Contra Costa County, CA 33 km (20 mi) WNW earthquakes near Contra Costa County
San Joaquin County, CA 34 km (21 mi) ENE earthquakes near San Joaquin County
Stanislaus County, CA 60 km (37 mi) ESE earthquakes near Stanislaus County
Solano County, CA 60 km (37 mi) NNW earthquakes near Solano County
Santa Clara County, CA 64 km (40 mi) S earthquakes near Santa Clara County

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

Aftershocks so far

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

  1. 1.8 10km E of Alum Rock, CA
  2. 1.5 12km E of Blackhawk, CA
  3. 1.6 14km SSE of Livermore, CA
  4. 2.1 9km NNE of Alum Rock, CA
  5. 1.5 9km NNE of Alum Rock, CA
  6. 1.8 2km NE of San Leandro, CA
  7. 2.3 2km SSE of Concord, CA
  8. 2.0 3km E of Union City, CA
  9. 1.7 5km WNW of Sunol, CA
  10. 1.7 3km WNW of Diablo, CA
  11. 2.3 8km E of Alum Rock, CA
  12. 1.7 11km SE of Livermore, CA
  13. 1.6 5km SW of Pacheco, CA
  14. 2.7 3km NNE of San Ramon, CA
  15. 2.4 1km N of Vine Hill, 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.