Earthquake · reviewed by a seismologist
M 1.6md
3km SSW of Half Moon Bay, CA
- When
- Magnitude
- M 1.6 (md)
- Depth
- 9.9 km below the surface
- Felt
- no reports yet
- Nearest
- San Mateo County, 7 km ESE
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1748 days ago
This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.
How big was it?
This earthquake released about 9 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 1,700,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,200,000× the energy of this one
- Around the size people start to feel M 3.0 110× the energy of this one
- This earthquake M 1.6 about 9 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 37.4352, -122.4405. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction | |
|---|---|---|---|
| San Mateo County, CA | 7 km (4 mi) | WNW of here | earthquakes near San Mateo County |
| Alameda County, CA | 52 km (32 mi) | WSW of here | earthquakes near Alameda County |
| Santa Cruz County, CA | 61 km (38 mi) | NW of here | earthquakes near Santa Cruz County |
| San Francisco County, CA | 61 km (38 mi) | ESE of here | earthquakes near San Francisco County |
| Contra Costa County, CA | 69 km (43 mi) | SW of here | earthquakes near Contra Costa County |
| Santa Clara County, CA | 71 km (44 mi) | WNW of here | earthquakes near Santa Clara County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
37 earthquakes have been recorded within 50 km since this one.
- 1.8 7km SSE of Portola Valley, CA
- 1.7 1km W of Pacifica, CA
- 2.2 1km WSW of Pacifica, CA
- 1.6 3km E of Oakland, CA
- 1.5 7km ESE of Fremont, CA
- 1.6 6km SSE of Portola Valley, CA
- 2.5 6km SSE of Portola Valley, CA
- 1.9 8km S of Sunol, CA
- 2.2 34km W of Bonny Doon, CA
- 2.1 1km E of Piedmont, CA
- 2.0 4km SSE of Highlands-Baywood Park, CA
- 1.9 2km N of Castro Valley, CA
- 1.6 5km E of Fremont, CA
- 1.6 7km S of Muir Beach, CA
- 1.8 3km SW 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.
For this area
The largest earthquake within 50 km in our catalogue was M 4.4 on 2018-01-04 — it released about 12,000 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.