Earthquake near East Foothills, CA

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 16 km (10 mi) from the epicentre. In East Foothills, 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.

Likely felt in: East Foothills 6 km, intensity II · Milpitas 12 km, intensity II · San Jose 14 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 44 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 340,000× the energy of this one
2. Magna, Utah 2020 M 5.7 240,000× the energy of this one
3. Around the size people start to feel M 3.0 22× the energy of this one
4. This earthquake M 2.1 about 44 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 20 earthquakes of M5 or more within 50 km; the five largest:

1. 6.9 The 1989 Loma Prieta, California Earthquake · 44 km SSW of this epicentre Oct 18, 1989
2. 6.5 Near Morgan Hill, California · 37 km SSE of this epicentre Jul 1, 1911
3. 6.2 Near San Jose, California · 14 km S of this epicentre Aug 3, 1903
4. 6.2 The 1984 Morgan Hill, California Earthquake · 15 km SSE of this epicentre Apr 24, 1984
5. 6.1 Near San Jose, California · 25 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 37.4270, -121.7737. Map © OpenStreetMap contributors.

Nearby places

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

Aftershocks so far

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

1. 1.6 3 km S of Loyola, California 19:31 UTC
2. 1.6 10 km NNE of East Foothills, California 09:07 UTC
3. 1.7 14 km E of Seven Trees, California 05:17 UTC
4. 1.9 14 km E of Seven Trees, California 05:16 UTC
5. 1.7 10 km SW of Brentwood, California 02:32 UTC
6. 1.5 3 km S of Loyola, California 18:56 UTC
7. 1.6 6 km SE of Sunol, California 06:50 UTC
8. 1.5 2 km SSE of Pleasanton, California 02:02 UTC
9. 1.7 3 km SSE of Portola Valley, California 00:36 UTC
10. 2.1 3 km SSE of Portola Valley, California 22:32 UTC
11. 1.9 7 km WSW of Gilroy, California 16:18 UTC
12. 2.2 14 km N of Morgan Hill, California 14:33 UTC
13. 2.0 3 km S of Loyola, California 19:34 UTC
14. 1.6 11 km W of Saratoga, California 18:45 UTC
15. 1.6 9 km NNE of East Foothills, California 11:33 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 10:03 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.