Earthquake · reviewed by a seismologist
M 1.5md
Earthquake near San Lorenzo, CA
No earthquake was likely felt in San Lorenzo in the 24 hours to 11:41 pm PST (07:41 UTC). The last one was M 2.4, 19 km (12 mi) ENE, at 4:29 pm PDT on 19 October 2026, estimated intensity II (weak) in town; 5 felt reports to USGS. Every earthquake near San Lorenzo
This page: a magnitude 1.5 earthquake was recorded in San Lorenzo, CA, at 3:39 am PDT on 3 September 2018 (10:39 UTC), 7.8 km deep.
USGS: 2km WSW of San Lorenzo, CA
13 km (8 mi) SE of Oakland, CA · in San Leandro, CA
- When
- 3:39 am PDT on 3 September 2018 ()
- Where
- in San Lorenzo, CA · earthquakes near San Lorenzo
- Magnitude
- M 1.5 (md)
- Depth
- 7.8 km below the surface
- Felt
- no reports yet
- Nearest
- Alameda County, 21 km E
- Nearest mapped fault
- Hayward fault, 4 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 2991 days ago
Earthquake alerts for San Lorenzo, CA
Get a notification in this browser when USGS records an earthquake near San Lorenzo, CA. No account or email needed.
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 6 km (4 mi) from the epicentre. 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: San Lorenzo in town, intensity II · San Leandro 5 km, intensity II · Castro Valley 5 km, intensity II · Hayward 6 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 5.4 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 2,800,000× the energy of this one
- Magna, Utah 2020 M 5.7 2,000,000× the energy of this one
- Around the size people start to feel M 3.0 180× the energy of this one
- This earthquake M 1.5 about 5.4 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
The largest earthquake within 50 km since 2016 was M 4.4 on 2018-01-04 — about 21,000 times the energy of this one.
Before 2016, the USGS record lists 8 earthquakes of M5 or more within 50 km; the five largest:
- 7.9 The 1906 San Francisco, California Earthquake · 37 km WNW of this epicentre
- 5.8 The 1980 Livermore, California Earthquake · 38 km ENE of this epicentre
- 5.7 15 km NE of East Foothills, California · 46 km ESE of this epicentre
- 5.5 6 km NNE of East Foothills, California · 42 km SE of this epicentre
- 5.4 9 km NE of Livermore, California · 39 km ENE 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 37.6777, -122.1442. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Alameda County, CA | 21 km (13 mi) | E | earthquakes near Alameda County |
| Contra Costa County, CA | 32 km (20 mi) | NNE | earthquakes near Contra Costa County |
| San Mateo County, CA | 35 km (22 mi) | SW | earthquakes near San Mateo County |
| Santa Clara County, CA | 65 km (40 mi) | SE | earthquakes near Santa Clara County |
| Marin County, CA | 67 km (42 mi) | NW | earthquakes near Marin County |
| Solano County, CA | 68 km (42 mi) | NNE | earthquakes near Solano County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
54 earthquakes have been recorded within 50 km since this one.
- 2.4 1km NW of Crockett, CA
- 1.6 8km NE of Alum Rock, CA
- 1.6 11km S of Portola Valley, CA
- 1.7 6km NE of Blackhawk, CA
- 1.7 3km S of Loyola, CA
- 1.6 2km NW of Crockett, CA
- 2.7 2km NW of Crockett, CA
- 3.5 2km NW of Crockett, CA
- 2.0 4km E of El Sobrante, CA
- 1.6 6km WNW of Mountain House, CA
- 1.7 4km SSW of Los Altos Hills, CA
- 2.8 6km WNW of Mountain House, CA
- 1.6 2km NW of Pacifica, CA
- 2.5 3km ESE of San Leandro, CA
- 1.5 16km SSE of Livermore, 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.