QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7md

Earthquake near Gustine, CA

No earthquake was likely felt in Gustine in the 24 hours to 3:11 am PST (11:11 UTC). The last one was M 3.1, 23 km (14 mi) WSW, at 9:18 pm PDT on 21 October 2026, estimated intensity II (weak) in town; 9 felt reports to USGS. Every earthquake near Gustine

This page: a magnitude 1.7 earthquake was recorded 8 km (5 mi) south of Gustine, CA, at 12:41 am PDT on 10 September 2021 (07:41 UTC), 9.2 km deep.

USGS: 8km S of Gustine, CA

73 km (45 mi) E of San Jose, CA · 38 km (23 mi) SSW of Turlock, CA

12:41 am PDT, Sep 10, 2021 · · 9.2 km deep · released about 12 lb of TNT

10 km30 km60 km120 km N Merced County 25 kmStanislaus County 42 kmSanta Clara County 61 kmSan Benito County 65 kmSan Joaquin County 86 kmSanta Cruz County 91 kmAlameda County 95 kmMariposa County 106 kmMonterey County 109 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
12:41 am PDT on 10 September 2021 ()
Where
8 km (5 mi) south of Gustine, CA · earthquakes near Gustine
Magnitude
M 1.7 (md)
Depth
9.2 km below the surface
Felt
no reports yet
Nearest
Merced County, 25 km E
Nearest mapped fault
Great Valley thrust fault system, 5 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 1889 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 9 km (6 mi) from the epicentre. In Gustine, 8 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: Gustine 8 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 12 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,200,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 870,000× the energy of this one
  3. Around the size people start to feel M 3.0 78× the energy of this one
  4. This earthquake M 1.7 about 12 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 2 earthquakes of M5 or more within 50 km:

  1. 5.8 The 1979 Coyote Lake, California Earthquake · 46 km WSW of this epicentre
  2. 5.5 3 km ENE of Tres Pinos, California · 49 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 37.1883, -121.0057. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Merced County, CA 25 km (16 mi) E earthquakes near Merced County
Stanislaus County, CA 42 km (26 mi) N earthquakes near Stanislaus County
Santa Clara County, CA 61 km (38 mi) W earthquakes near Santa Clara County
San Benito County, CA 65 km (40 mi) S earthquakes near San Benito County
San Joaquin County, CA 86 km (54 mi) NNW earthquakes near San Joaquin County
Santa Cruz County, CA 91 km (57 mi) WSW earthquakes near Santa Cruz County

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

Aftershocks so far

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

  1. 2.2 8km ENE of Gilroy, CA
  2. 1.7 4km NNW of Hollister, CA
  3. 1.5 8km ENE of Gilroy, CA
  4. 1.6 23km WSW of Patterson, CA
  5. 1.6 6km NE of Ridgemark, CA
  6. 1.6 32km SW of South Dos Palos, CA
  7. 2.2 16km W of Los Banos, CA
  8. 1.7 7km ENE of Gilroy, CA
  9. 2.3 9km E of Gilroy, CA
  10. 1.9 9km E of Gilroy, CA
  11. 1.7 27km NE of Hollister, CA
  12. 2.1 26km SW of Gustine, CA
  13. 1.9 5km NNW of Hollister, CA
  14. 1.8 7km ENE of Gilroy, CA
  15. 2.1 12km ENE of Morgan 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.