Earthquake near San Rafael, 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 13 km (8 mi) from the epicentre. In San Rafael, 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: San Rafael 6 km, intensity II · San Pablo 10 km, intensity II · Richmond 11 km, intensity II · Tamalpais-Homestead Valley 13 km, intensity II. Estimated for each town centre; each link is that town's own record.

USGS catalogues this as quarry blast, not an earthquake.

How big was it?

This earthquake released about 15 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

1. Mineral, Virginia 2011 M 5.8 1,000,000× the energy of this one
2. Magna, Utah 2020 M 5.7 730,000× the energy of this one
3. Around the size people start to feel M 3.0 65× the energy of this one
4. This earthquake M 1.8 about 15 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 4.5 on 2019-10-15 — about 10,000 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 · 26 km SSW of this epicentre Apr 18, 1906
2. 6.0 The 2014 South Napa, California Earthquake · 30 km NNE of this epicentre Aug 24, 2014
3. 5.3 The 1957 San Francisco, California Earthquake · 34 km S of this epicentre Mar 22, 1957
4. 5.3 3 km E of Bloomfield, California · 48 km NW of this epicentre Oct 2, 1969
5. 5.3 Northern California · 50 km NW of this epicentre Oct 2, 1969

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 37.9762, -122.4633. Map © OpenStreetMap contributors.

Nearby places

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

Aftershocks so far

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

1. 1.6 0 km WSW of Diablo, CA 02:45 UTC
2. 2.5 3 km NNW of Piedmont, CA 07:13 UTC
3. 1.8 6 km ESE of Santa Venetia, CA 18:31 UTC
4. 1.5 6 km NNE of Orinda, CA 04:31 UTC
5. 2.1 10 km WSW of San Lorenzo, CA 04:30 UTC
6. 1.7 2 km ENE of San Leandro, CA 15:09 UTC
7. 2.0 7 km NW of San Francisco Zoo, CA 00:35 UTC
8. 1.9 3 km ESE of South San Francisco, CA 14:33 UTC
9. 2.0 1 km E of Pacifica, CA 17:41 UTC
10. 2.3 1 km E of Pacifica, CA 16:54 UTC
11. 2.2 1 km NW of Green Valley, CA 19:13 UTC
12. 2.4 4 km W of Glen Ellen, CA 15:35 UTC
13. 1.6 7 km WNW of Yountville, CA 18:59 UTC
14. 1.8 3 km WNW of Boyes Hot Springs, CA 00:59 UTC
15. 1.5 4 km ESE of Pacifica, CA 12:48 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 11:26 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.