Earthquake near Milpitas, 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 26 km (16 mi) from the epicentre. In Milpitas, 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: Milpitas 9 km, intensity III · San Jose 16 km, intensity II · Fremont 17 km, intensity II · Santa Clara 18 km, intensity II · Newark 20 km, intensity II · Pleasanton 22 km, intensity II · Sunnyvale 22 km, intensity II · Union City 22 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 480 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 32,000× the energy of this one
2. Magna, Utah 2020 M 5.7 22,000× the energy of this one
3. Around the size people start to feel M 3.0 2× the energy of this one
4. This earthquake M 2.8 about 480 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 4.1 on 2017-10-10 — about 86 times the energy of this one.

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 · 49 km S of this epicentre Oct 18, 1989
2. 6.5 Near Morgan Hill, California · 43 km SSE of this epicentre Jul 1, 1911
3. 6.2 Near San Jose, California · 19 km S of this epicentre Aug 3, 1903
4. 6.2 The 1984 Morgan Hill, California Earthquake · 22 km SE of this epicentre Apr 24, 1984
5. 6.1 Near San Jose, California · 30 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 37.4713, -121.8210. Map © OpenStreetMap contributors.

Nearby places

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

Aftershocks so far

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

1. 1.6 2km ESE of Pleasanton, CA 01:57 UTC
2. 2.0 11km SSE of Portola Valley, CA 01:26 UTC
3. 2.5 3km ENE of Oakland, CA 19:07 UTC
4. 1.8 10km E of Alum Rock, CA 02:42 UTC
5. 1.6 8km NE of Alum Rock, CA 08:51 UTC
6. 1.6 11km S of Portola Valley, CA 06:05 UTC
7. 1.7 6km NE of Blackhawk, CA 05:16 UTC
8. 1.7 3km S of Loyola, CA 21:23 UTC
9. 1.6 6km WNW of Mountain House, CA 22:57 UTC
10. 1.7 4km SSW of Los Altos Hills, CA 08:19 UTC
11. 2.8 6km WNW of Mountain House, CA 01:58 UTC
12. 2.5 3km ESE of San Leandro, CA 19:28 UTC
13. 2.1 15km E of Seven Trees, CA 12:50 UTC
14. 1.5 16km SSE of Livermore, CA 21:16 UTC
15. 1.7 2km E of Hayward, CA 06:24 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 08:50 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.