Earthquake · reviewed by a seismologist
M 1.7md
Earthquake near Gustine, CA
No earthquake was likely felt in Gustine in the 24 hours to 3:38 am PST (11:38 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 18 km (11 mi) south-southwest of Gustine, CA, at 6:22 am PDT on 30 August 2021 (13:22 UTC), 7.2 km deep.
USGS: 18km SSW of Gustine, CA
69 km (43 mi) ESE of San Jose, CA · 47 km (29 mi) ENE of Gilroy, CA
- When
- 6:22 am PDT on 30 August 2021 ()
- Where
- 18 km (11 mi) south-southwest of Gustine, CA · earthquakes near Gustine
- Magnitude
- M 1.7 (md)
- Depth
- 7.2 km below the surface
- Felt
- no reports yet
- Nearest
- Merced County, 33 km ENE
- Nearest mapped fault
- Great Valley thrust fault system, 4 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 1898 days ago
Earthquake alerts for Gustine, CA
Get a notification in this browser when USGS records an earthquake near Gustine, CA. No account or email needed.
Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
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 Gustine, 18 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: Los Banos, Newman.
How big was it?
This earthquake released about 11 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.
- Mineral, Virginia 2011 M 5.8 1,400,000× the energy of this one
- Magna, Utah 2020 M 5.7 970,000× the energy of this one
- Around the size people start to feel M 3.0 86× the energy of this one
- This earthquake M 1.7 about 11 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 8 earthquakes of M5 or more within 50 km; the five largest:
- 5.9 10 km SE of Tres Pinos, California · 43 km SSW of this epicentre
- 5.8 The 1979 Coyote Lake, California Earthquake · 39 km W of this epicentre
- 5.5 7 km SW of Hollister, California · 48 km SW of this epicentre
- 5.5 3 km ENE of Tres Pinos, California · 38 km SSW of this epicentre
- 5.3 3 km SW of Gilroy, California · 49 km WSW 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 37.1038, -121.0728. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Merced County, CA | 33 km (20 mi) | ENE | earthquakes near Merced County |
| Stanislaus County, CA | 51 km (32 mi) | N | earthquakes near Stanislaus County |
| San Benito County, CA | 55 km (34 mi) | S | earthquakes near San Benito County |
| Santa Clara County, CA | 56 km (35 mi) | WNW | earthquakes near Santa Clara County |
| Santa Cruz County, CA | 84 km (52 mi) | W | earthquakes near Santa Cruz County |
| San Joaquin County, CA | 94 km (58 mi) | N | earthquakes near San Joaquin County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
20 earthquakes have been recorded within 50 km since this one.
- 2.3 15km SE of Tres Pinos, CA
- 1.6 8km ENE of Gilroy, CA
- 2.4 6km N of Hollister, CA
- 1.6 7km WSW of Ridgemark, CA
- 1.8 10km ENE of Morgan Hill, CA
- 2.1 7km NE of San Martin, CA
- 1.9 22km NE of Morgan Hill, CA
- 1.5 3km SW of Hollister, CA
- 1.9 6km ENE of Hollister, CA
- 2.3 6km SSW of Gilroy, CA
- 2.1 8km SSW of Tres Pinos, CA
- 1.9 6km S of Tres Pinos, CA
- 2.1 12km NNE of Hollister, CA
- 2.4 6km NNE of Los Banos, CA
- 2.1 5km NNE of Los Banos, 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
- The official USGS event page — the source of record for every value above
- Did you feel it? Report it to USGS — reports go to USGS, not to us
- ShakeMap for this event, when USGS has produced one
QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.