Earthquake near Foster City, 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 8 km (5 mi) from the epicentre. In Foster City, 4 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: Foster City 4 km, intensity II · San Mateo 4 km, intensity II · Burlingame 7 km, intensity II · Belmont 8 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 5.7 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 2,600,000× the energy of this one
2. Magna, Utah 2020 M 5.7 1,900,000× the energy of this one
3. Around the size people start to feel M 3.0 170× the energy of this one
4. This earthquake M 1.5 about 5.7 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 19,000 times the energy of this one.

Before 2016, the USGS record lists 5 earthquakes of M5 or more within 50 km:

1. 7.9 The 1906 San Francisco, California Earthquake · 29 km NW of this epicentre Apr 18, 1906
2. 5.8 7 km NNW of Boulder Creek, California · 46 km SSE of this epicentre Sep 5, 1955
3. 5.5 6 km NNE of East Foothills, California · 49 km ESE of this epicentre Oct 31, 2007
4. 5.3 The 1957 San Francisco, California Earthquake · 19 km WNW of this epicentre Mar 22, 1957
5. 5.1 7 km SW of Monte Sereno, California · 49 km SSE of this epicentre Oct 18, 1989

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 37.5908, -122.2900. 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. 1.5 2km WSW of San Lorenzo, CA 10:39 UTC
2. 3.4 9km ENE of Milpitas, CA 02:10 UTC
3. 2.1 5km E of Union City, CA 17:15 UTC
4. 1.6 6km SSW of Stinson Beach, CA 15:38 UTC
5. 1.6 8km NE of Alum Rock, CA 12:32 UTC
6. 1.5 3km NNW of Orinda, CA 02:08 UTC
7. 1.8 2km E of Alamo, CA 20:22 UTC
8. 1.5 2km E of Alamo, CA 20:53 UTC
9. 1.6 0km E of Pacifica, CA 09:26 UTC
10. 1.9 9km S of Muir Beach, CA 08:14 UTC
11. 1.6 4km S of Loyola, CA 18:09 UTC
12. 1.7 2km SW of Concord, CA 06:13 UTC
13. 2.1 2km SSW of Dublin, CA 20:30 UTC
14. 1.6 3km S of Loyola, CA 17:51 UTC
15. 2.3 5km ESE of Blackhawk, CA 08:20 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 18:59 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.