Earthquake · reviewed by a seismologist
M 1.8md
5km WSW of Colma, CA
- When
- Magnitude
- M 1.8 (md)
- Depth
- 5.5 km below the surface
- Felt
- 4 reports · strongest reported intensity II
- Nearest
- San Mateo County, 30 km SSE
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1326 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.
- Mineral, Virginia 2011 M 5.8 870,000× the energy of this one
- Magna, Utah 2020 M 5.7 620,000× the energy of this one
- Around the size people start to feel M 3.0 55× the energy of this one
- 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 37.6645, -122.5130. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction | |
|---|---|---|---|
| San Mateo County, CA | 30 km (19 mi) | NNW of here | earthquakes near San Mateo County |
| San Francisco County, CA | 46 km (29 mi) | E of here | earthquakes near San Francisco County |
| Marin County, CA | 48 km (30 mi) | SSE of here | earthquakes near Marin County |
| Alameda County, CA | 53 km (33 mi) | W of here | earthquakes near Alameda County |
| Contra Costa County, CA | 57 km (35 mi) | WSW of here | earthquakes near Contra Costa County |
| Solano County, CA | 84 km (52 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
49 earthquakes have been recorded within 50 km since this one.
- 1.6 4km WNW of San Francisco Zoo, CA
- 1.6 7km S of Muir Beach, CA
- 2.0 3km SSW of Port Costa, CA
- 2.1 1km WNW of Kensington, CA
- 1.7 2km ENE of Berkeley, CA
- 2.0 7km SSE of Portola Valley, CA
- 2.0 2km SE of Portola Valley, CA
- 1.9 7km SSE of Portola Valley, CA
- 2.1 7km SSE of Portola Valley, CA
- 2.4 1km N of Pacifica, CA
- 2.1 5km W of Hillsborough, CA
- 1.8 2km N of Lafayette, CA
- 2.2 5km WSW of San Francisco Zoo, CA
- 1.8 4km SSE of Highlands-Baywood Park, CA
- 2.1 6km NNE of San Leandro, 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 4.4 on 2018-01-04 — it released about 6,500 times the energy of this one.
From the QuakeIndex catalogue, built from the USGS FDSN event service.
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.