Earthquake near East Foothills, CA

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 25 km (16 mi) from the epicentre. In East Foothills, 9 km away, the estimate is intensity III (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: East Foothills 9 km, intensity III · Milpitas 12 km, intensity III · San Jose 17 km, intensity II · Santa Clara 19 km, intensity II · Fremont 22 km, intensity II · Campbell 24 km, intensity II · Pleasanton 25 km, intensity II · Newark 25 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 450 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.8 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 34,000× the energy of this one
2. Magna, Utah 2020 M 5.7 24,000× the energy of this one
3. Around the size people start to feel M 3.0 2.1× the energy of this one
4. This earthquake M 2.8 about 450 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 19 earthquakes of M5 or more within 50 km; the five largest:

1. 6.9 The 1989 Loma Prieta, California Earthquake · 47 km SSW of this epicentre Oct 18, 1989
2. 6.5 Near Morgan Hill, California · 40 km SSE of this epicentre Jul 1, 1911
3. 6.2 Near San Jose, California · 17 km S of this epicentre Aug 3, 1903
4. 6.2 The 1984 Morgan Hill, California Earthquake · 18 km SSE of this epicentre Apr 24, 1984
5. 6.1 Near San Jose, California · 28 km S of this epicentre Jun 11, 1903

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 37.4543, -121.7750. Map © OpenStreetMap contributors.

Nearby places

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

Aftershocks so far

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

1. 1.8 9 km NE of Blackhawk, California 15:01 UTC
2. 2.1 4 km WSW of Saratoga, California 11:28 UTC
3. 1.6 10 km WSW of Brentwood, California 17:51 UTC
4. 1.6 9 km NNE of San Martin, California 08:18 UTC
5. 1.8 14 km E of Seven Trees, California 09:16 UTC
6. 2.2 5 km ENE of East Foothills, California 10:59 UTC
7. 1.8 3 km SE of Hayward, California 23:58 UTC
8. 1.9 3 km N of Diablo, California 21:53 UTC
9. 2.1 6 km NE of East Foothills, California 14:10 UTC
10. 1.5 7 km NW of Livermore, California 10:52 UTC
11. 2.1 8 km SSE of Sunol, California 05:19 UTC
12. 1.5 1 km S of Alamo, California 08:03 UTC
13. 1.6 2 km WNW of Los Altos Hills, California 20:30 UTC
14. 2.0 2 km WSW of Blackhawk, California 14:58 UTC
15. 1.8 3 km S of Loyola, California 17:34 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 09:20 UTC. 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.