Earthquake near Castro Valley, 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 11 km (7 mi) from the epicentre. 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: Castro Valley in town, intensity II · Hayward 4 km, intensity II · San Lorenzo 4 km, intensity II · San Leandro 6 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 10 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.

1. Mineral, Virginia 2011 M 5.8 1,500,000× the energy of this one
2. Magna, Utah 2020 M 5.7 1,100,000× the energy of this one
3. Around the size people start to feel M 3.0 95× the energy of this one
4. This earthquake M 1.7 about 10 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 4.4 on 2018-01-04 — about 11,000 times the energy of this one.

Before 2016, the USGS record lists 8 earthquakes of M5 or more within 50 km; the five largest:

1. 7.9 The 1906 San Francisco, California Earthquake · 40 km W of this epicentre Apr 18, 1906
2. 5.8 The 1980 Livermore, California Earthquake · 33 km ENE of this epicentre Jan 24, 1980
3. 5.7 15 km NE of East Foothills, California · 44 km SE of this epicentre Mar 31, 1986
4. 5.5 6 km NNE of East Foothills, California · 41 km SE of this epicentre Oct 31, 2007
5. 5.4 9 km NE of Livermore, California · 35 km E of this epicentre Jan 27, 1980

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 37.7027, -122.1002. Map © OpenStreetMap contributors.

Nearby places

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

Aftershocks so far

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

1. 1.8 3km NW of Diablo, CA 03:27 UTC
2. 1.5 3km NW of Diablo, CA 01:30 UTC
3. 2.7 3km NW of Diablo, CA 01:24 UTC
4. 1.6 4km ENE of Oakland, CA 06:52 UTC
5. 1.7 4km ESE of Union City, CA 08:57 UTC
6. 1.5 4km NNW of Foster City, CA 10:18 UTC
7. 2.2 3km ENE of Oakland, CA 22:52 UTC
8. 2.1 2km ENE of San Ramon, CA 07:59 UTC
9. 3.5 3km ENE of Oakland, CA 02:18 UTC
10. 1.9 13km SE of Livermore, CA 23:55 UTC
11. 1.8 2km ENE of San Ramon, CA 15:06 UTC
12. 1.6 2km ENE of San Ramon, CA 15:05 UTC
13. 1.9 3km WSW of Portola Valley, CA 10:14 UTC
14. 2.0 3km W of Pittsburg, CA 07:26 UTC
15. 2.0 7km NW of San Francisco Zoo, CA 00:15 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 11:17 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.