10km NE of Milpitas, CA

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 77 people have reported feeling it to USGS.

How big was it?

This earthquake released about 630 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.9 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 24,000× the energy of this one
2. Magna, Utah 2020 M 5.7 17,000× the energy of this one
3. Around the size people start to feel M 3.0 1.5× the energy of this one
4. This earthquake M 2.9 about 630 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.

Where

Epicentre 37.4925, -121.8293. 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. 2.1 10km NE of Milpitas, CA 16:21 UTC
2. 2.0 11km NE of Milpitas, CA 17:52 UTC
3. 2.9 10km NE of Milpitas, CA 15:39 UTC
4. 1.7 10km NE of Milpitas, CA 12:19 UTC
5. 2.6 10km NNE of Milpitas, CA 08:38 UTC
6. 2.0 7km S of Livermore, CA 17:06 UTC
7. 1.9 7km S of Livermore, CA 16:52 UTC
8. 3.3 10km NE of Milpitas, CA 16:02 UTC
9. 2.9 10km NE of Milpitas, CA 15:36 UTC
10. 2.7 10km NE of Milpitas, CA 15:16 UTC
11. 1.7 1km SW of Diablo, CA 11:25 UTC
12. 1.9 10km NE of Milpitas, CA 08:15 UTC
13. 1.6 10km NE of Milpitas, CA 07:14 UTC
14. 1.8 10km NE of Milpitas, CA 06:05 UTC
15. 2.1 10km NE of Milpitas, CA 06:03 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 10:46 UTC. QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

For this area

The largest earthquake within 50 km in our catalogue was M 4.3 on 2019-07-16 — it released about 140 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

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.