Earthquake · reviewed by a seismologist
M 2.2md
Earthquake near Half Moon Bay, CA
No earthquake was likely felt in Half Moon Bay in the 24 hours to 11:17 am PST (19:17 UTC). The last one was M 2.7, 18 km (11 mi) N, at 5:17 pm PDT on 28 October 2026, estimated intensity II (weak) in town; 526 felt reports to USGS. Every earthquake near Half Moon Bay
This page: a magnitude 2.2 earthquake was recorded 8 km (5 mi) south-southwest of Half Moon Bay, CA, at 5:44 pm PST on 12 November 2024 (01:44 UTC), 6.9 km deep. 1 person has reported feeling it to USGS.
USGS: 8 km SSW of Half Moon Bay, CA
43 km (27 mi) S of San Francisco, CA · 23 km (14 mi) SSW of San Mateo, CA
- When
- 5:44 pm PST on 12 November 2024 ()
- Where
- 8 km (5 mi) south-southwest of Half Moon Bay, CA · earthquakes near Half Moon Bay
- Magnitude
- M 2.2 (md)
- Depth
- 6.9 km below the surface
- Felt
- 1 report · strongest reported intensity II
- Nearest
- San Mateo County, 8 km ENE
- Nearest mapped fault
- San Gregorio fault, under 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 225 days ago
Earthquake alerts for Half Moon Bay, CA
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Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
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 17 km (11 mi) from the epicentre. In Half Moon Bay, 8 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: Half Moon Bay 8 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 52 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.
- Mineral, Virginia 2011 M 5.8 290,000× the energy of this one
- Magna, Utah 2020 M 5.7 200,000× the energy of this one
- Around the size people start to feel M 3.0 18× the energy of this one
- This earthquake M 2.2 about 52 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
No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.
Before 2016, the USGS record lists 7 earthquakes of M5 or more within 50 km; the five largest:
- 7.9 The 1906 San Francisco, California Earthquake · 41 km NNW of this epicentre
- 5.8 7 km NNW of Boulder Creek, California · 35 km SE of this epicentre
- 5.5 Santa Cruz Mountains, California · 47 km ESE of this epicentre
- 5.5 1 km WNW of Davenport, California · 47 km SSE of this epicentre
- 5.3 The 1957 San Francisco, California Earthquake · 31 km N 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 37.3900, -122.4522. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| San Mateo County, CA | 8 km (5 mi) | ENE | earthquakes near San Mateo County |
| Alameda County, CA | 56 km (35 mi) | ENE | earthquakes near Alameda County |
| Santa Cruz County, CA | 58 km (36 mi) | SE | earthquakes near Santa Cruz County |
| San Francisco County, CA | 63 km (39 mi) | NW | earthquakes near San Francisco County |
| Santa Clara County, CA | 70 km (43 mi) | ESE | earthquakes near Santa Clara County |
| Contra Costa County, CA | 74 km (46 mi) | NE | earthquakes near Contra Costa County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
51 earthquakes have been recorded within 50 km since this one.
- 1.8 5 km S of Portola Valley, CA
- 1.8 5 km S of Loyola, CA
- 1.5 3 km WSW of San Francisco Zoo, CA
- 2.4 5 km WSW of San Francisco Zoo, CA
- 1.7 3 km SSE of Pacifica, CA
- 2.0 3 km SSE of Pacifica, CA
- 1.7 4 km WSW of Millbrae, CA
- 1.5 4 km SE of Oakland, CA
- 1.6 4 km WSW of Millbrae, CA
- 1.6 5 km S of Portola Valley, CA
- 1.6 5 km S of Portola Valley, CA
- 2.5 5 km S of Portola Valley, CA
- 2.3 2 km E of Hayward, CA
- 1.8 2 km E of Hayward, CA
- 2.1 2 km E of Hayward, 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.