QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

Earthquake near Gilroy, CA

Yes: an earthquake was likely felt in Gilroy in the last 24 hours. M 1.6, 9 km (5 mi) E of Gilroy, at 1:22 am PST on 12 November 2026 (09:22 UTC); the estimated shaking in Gilroy was intensity II (weak). Every earthquake near Gilroy

This page: a magnitude 1.8 earthquake was recorded 7 km (5 mi) east-northeast of Gilroy, CA, at 11:02 am PST on 10 December 2021 (19:02 UTC), 8.8 km deep.

USGS: 7km ENE of Gilroy, CA

9 km (5 mi) ENE of Gilroy, CA · 42 km (26 mi) SE of San Jose, CA

11:02 am PST, Dec 10, 2021 · · 8.8 km deep · released about 14 lb of TNT

10 km30 km60 km120 km N Santa Clara County 28 kmSanta Cruz County 46 kmSan Benito County 58 kmMerced County 70 kmStanislaus County 73 kmAlameda County 79 kmMonterey County 89 kmSan Mateo County 89 kmSan Joaquin County 103 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
11:02 am PST on 10 December 2021 ()
Where
7 km (5 mi) east-northeast of Gilroy, CA · earthquakes near Gilroy
Magnitude
M 1.8 (md)
Depth
8.8 km below the surface
Felt
no reports yet
Nearest
Santa Clara County, 28 km NW
Nearest mapped fault
Calaveras fault, under 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 1793 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 10 km (6 mi) from the epicentre. In Gilroy, 7 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.

Likely felt in: Gilroy 7 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 14 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,100,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 760,000× the energy of this one
  3. Around the size people start to feel M 3.0 68× the energy of this one
  4. This earthquake M 1.8 about 14 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 4.7 on 2019-10-15 — about 25,000 times the energy of this one.

Before 2016, the USGS record lists 28 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.9 The 1989 Loma Prieta, California Earthquake · 35 km W of this epicentre
  2. 6.5 Near Morgan Hill, California · 16 km NW of this epicentre
  3. 6.2 Near San Jose, California · 41 km NW of this epicentre
  4. 6.2 The 1984 Morgan Hill, California Earthquake · 36 km NNW of this epicentre
  5. 6.1 Near San Jose, California · 34 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 37.0265, -121.4890. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Santa Clara County, CA 28 km (17 mi) NW earthquakes near Santa Clara County
Santa Cruz County, CA 46 km (29 mi) W earthquakes near Santa Cruz County
San Benito County, CA 58 km (36 mi) SE earthquakes near San Benito County
Merced County, CA 70 km (44 mi) ENE earthquakes near Merced County
Stanislaus County, CA 73 km (46 mi) NE earthquakes near Stanislaus County
Alameda County, CA 79 km (49 mi) NNW earthquakes near Alameda County

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

Aftershocks so far

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

  1. 1.7 1km W of San Juan Bautista, CA
  2. 3.1 1km W of San Juan Bautista, CA
  3. 2.5 4km NW of Aromas, CA
  4. 1.6 1km WNW of San Juan Bautista, CA
  5. 2.2 1km W of San Juan Bautista, CA
  6. 1.6 6km NE of Ridgemark, CA
  7. 1.8 1km W of San Juan Bautista, CA
  8. 1.5 3km E of Aromas, CA
  9. 2.9 4km WSW of San Juan Bautista, CA
  10. 2.7 16km E of Seven Trees, CA
  11. 2.0 11km S of Tres Pinos, CA
  12. 2.1 11km S of Tres Pinos, CA
  13. 2.0 6km SW of Gilroy, CA
  14. 2.8 4km SE of Aromas, CA
  15. 1.5 16km SSE of Tres Pinos, 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.