QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

4km W of San Francisco Zoo, CA

· 13 km deep · released about 17 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N San Mateo County 39 kmMarin County 39 kmSan Francisco County 43 kmContra Costa County 56 kmAlameda County 56 kmSolano County 80 kmNapa County 88 kmSanta Cruz County 93 kmSonoma 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
Magnitude
M 1.8 (md)
Depth
13 km below the surface
Felt
4 reports · strongest reported intensity III
Nearest
San Mateo County, 39 km SSE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1511 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 4 people have reported feeling it to USGS.

How big was it?

This earthquake released about 17 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 5.8 900,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 640,000× the energy of this one
  3. Around the size people start to feel M 3.0 57× the energy of this one
  4. This earthquake M 1.8 about 17 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 37.7345, -122.5448. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
San Mateo County, CA 39 km (24 mi) NNW of here earthquakes near San Mateo County
Marin County, CA 39 km (24 mi) SSE of here earthquakes near Marin County
San Francisco County, CA 43 km (27 mi) E of here earthquakes near San Francisco County
Contra Costa County, CA 56 km (35 mi) WSW of here earthquakes near Contra Costa County
Alameda County, CA 56 km (35 mi) W of here earthquakes near Alameda County
Solano County, CA 80 km (49 mi) SW of here earthquakes near Solano County

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

Aftershocks so far

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

  1. 1.9 2km SE of Pacheco, CA
  2. 3.3 7km S of Muir Beach, CA
  3. 2.6 0km E of San Pablo, CA
  4. 1.9 2km NNE of San Leandro, CA
  5. 1.7 2km E of Berkeley, CA
  6. 2.5 0km SE of Rollingwood, CA
  7. 1.6 0km SE of Rollingwood, CA
  8. 2.1 4km ESE of Hayward, CA
  9. 1.6 2km N of El Cerrito, CA
  10. 1.8 3km ESE of Berkeley, CA
  11. 1.6 6km W of San Francisco Zoo, CA
  12. 1.6 3km ESE of Highlands-Baywood Park, CA
  13. 1.7 1km WSW of Pleasant Hill, CA
  14. 1.5 3km NNW of Benicia, CA
  15. 1.6 6km ESE of Santa Venetia, 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.

For this area

The largest earthquake within 50 km in our catalogue was M 4.5 on 2019-10-15 — it released about 8,800 times the energy of this one.

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

On USGS

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