QuakeIndex

Earthquake · reviewed by a seismologist

M 2.2md

Earthquake near Daly City, CA

No earthquake was likely felt in Daly City in the 24 hours to 1:29 pm PST (21:29 UTC). The last one was M 2.7, 9 km (6 mi) S, at 5:17 pm PDT on 28 October 2026, estimated intensity III (weak) in town; 526 felt reports to USGS. Every earthquake near Daly City

This page: a magnitude 2.2 earthquake was recorded 5 km (3 mi) southwest of Daly City, CA, at 2:23 am PDT on 30 May 2021 (09:23 UTC), 12 km deep. 8 people have reported feeling it to USGS.

USGS: 4km WSW of Daly City, CA

14 km (9 mi) SW of San Francisco, CA · in Daly City, CA

2:23 am PDT, May 30, 2021 · · 12 km deep · released about 58 lb of TNT

10 km30 km60 km120 km N San Mateo County 31 kmSan Francisco County 46 kmMarin County 47 kmAlameda County 53 kmContra Costa County 56 kmSolano County 82 kmSanta Cruz County 86 kmSanta Clara County 88 kmNapa County 94 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
2:23 am PDT on 30 May 2021 ()
Where
5 km (3 mi) southwest of Daly City, CA · earthquakes near Daly City
Magnitude
M 2.2 (md)
Depth
12 km below the surface
Felt
8 reports · strongest reported intensity III
Nearest
San Mateo County, 31 km SSE
Nearest mapped fault
San Andreas fault, 1 km from its surface trace — near is not the same as on
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1988 days ago

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 Daly City, 5 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: Daly City 5 km, intensity II · Pacifica 7 km, intensity II · South San Francisco 9 km, intensity II · San Bruno 10 km, intensity II · Bayview-Hunters Point 13 km, intensity II · San Francisco 13 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 58 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.2 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 260,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 180,000× the energy of this one
  3. Around the size people start to feel M 3.0 16× the energy of this one
  4. This earthquake M 2.2 about 58 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 2,500 times the energy of this one.

Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:

  1. 7.9 The 1906 San Francisco, California Earthquake · 9 km NNW of this epicentre
  2. 5.3 The 1957 San Francisco, California Earthquake · 2 km ESE of this epicentre

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 37.6762, -122.5080. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
San Mateo County, CA 31 km (20 mi) SSE earthquakes near San Mateo County
San Francisco County, CA 46 km (29 mi) W earthquakes near San Francisco County
Marin County, CA 47 km (29 mi) NNW earthquakes near Marin County
Alameda County, CA 53 km (33 mi) E earthquakes near Alameda County
Contra Costa County, CA 56 km (35 mi) ENE earthquakes near Contra Costa County
Solano County, CA 82 km (51 mi) NE earthquakes near Solano County

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

Aftershocks so far

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

  1. 1.5 3km N of San Leandro, CA
  2. 3.4 3km N of San Leandro, CA
  3. 3.0 3km N of San Leandro, CA
  4. 1.5 14km SW of Portola Valley, CA
  5. 2.1 2km E of Hayward, CA
  6. 1.8 1km WNW of Walnut Creek, CA
  7. 1.8 5km WNW of Dublin, CA
  8. 1.9 4km SW of Newark, CA
  9. 1.7 5km NW of Dublin, CA
  10. 1.5 3km NNW of Union City, CA
  11. 1.6 5km NW of Dublin, CA
  12. 1.5 6km WNW of Dublin, CA
  13. 3.1 6km WNW of Dublin, CA
  14. 1.7 6km WNW of Dublin, CA
  15. 1.7 1km N of Bolinas, CA

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

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.