Earthquake · reviewed by a seismologist
M 2.5md
5 km WSW of Portola Valley, CA
- When
- Magnitude
- M 2.5 (md)
- Depth
- 4.1 km below the surface
- Felt
- 26 reports · strongest reported intensity III
- Nearest
- San Mateo County, 10 km NW
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 124 days ago
This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 26 people have reported feeling it to USGS.
How big was it?
This earthquake released about 170 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.5 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 89,000× the energy of this one
- Magna, Utah 2020 M 5.7 63,000× the energy of this one
- Around the size people start to feel M 3.0 5.6× the energy of this one
- This earthquake M 2.5 about 170 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 37.3637, -122.2835. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction | |
|---|---|---|---|
| San Mateo County, CA | 10 km (6 mi) | SE of here | earthquakes near San Mateo County |
| Alameda County, CA | 45 km (28 mi) | SW of here | earthquakes near Alameda County |
| Santa Cruz County, CA | 46 km (29 mi) | NNW of here | earthquakes near Santa Cruz County |
| Santa Clara County, CA | 55 km (34 mi) | WNW of here | earthquakes near Santa Clara County |
| Contra Costa County, CA | 68 km (42 mi) | SSW of here | earthquakes near Contra Costa County |
| San Francisco County, CA | 77 km (48 mi) | ESE of here | earthquakes near San Francisco County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
39 earthquakes have been recorded within 50 km since this one.
- 1.7 2 km ESE of Pacifica, CA
- 1.8 6 km E of Fremont, CA
- 2.6 7 km E of Fremont, CA
- 1.8 3 km NNE of San Leandro, CA
- 2.4 21 km WNW of Boulder Creek, CA
- 1.6 4 km NE of San Leandro, CA
- 2.0 4 km NE of San Leandro, CA
- 2.0 6 km SE of Lexington Hills, CA
- 1.7 2 km SSE of Pacifica, CA
- 1.8 2 km SE of Pacifica, CA
- 1.8 1 km ENE of Dublin, CA
- 2.3 2 km SE of Pacifica, CA
- 1.6 12 km NNW of Boulder Creek, CA
- 1.5 3 km SSW of San Francisco Zoo, CA
- 2.6 3 km SSW of San Francisco Zoo, 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
- 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.