Earthquake · reviewed by a seismologist
M 2.5md
Earthquake near Concord, CA
No earthquake was likely felt in Concord in the 24 hours to 10:16 pm PST (06:16 UTC). The last one was M 2.1, 5 km (3 mi) SW, at 4:05 am PST on 8 November 2026, estimated intensity II (weak) in town; 3 felt reports to USGS. Every earthquake near Concord
This page: a magnitude 2.5 earthquake was recorded 4 km (3 mi) southeast of Concord, CA, at 1:18 am PDT on 17 August 2026 (08:18 UTC), 16 km deep. 13 people have reported feeling it to USGS.
USGS: 2 km SE of Concord, CA
in Concord, CA
- When
- 1:18 am PDT on 17 August 2026 ()
- Where
- 4 km (3 mi) southeast of Concord, CA · earthquakes near Concord
- Magnitude
- M 2.5 (md)
- Depth
- 16 km below the surface
- Felt
- 13 reports · strongest reported intensity III
- Nearest
- Contra Costa County, 5 km SE
- Nearest mapped fault
- Greenville 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 64 days ago
Earthquake alerts for Concord, CA
Get a notification in this browser when USGS records an earthquake near Concord, 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 small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.
At this magnitude and depth, people at rest would likely notice it out to about 17 km (11 mi) from the epicentre. In Concord, 4 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: Concord 4 km, intensity II · Pleasant Hill 6 km, intensity II · Pacheco 8 km, intensity II · Walnut Creek 8 km, intensity II · Alamo 12 km, intensity II · Lafayette 13 km, intensity II · Pittsburg 13 km, intensity II · Martinez 14 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 200 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 75,000× the energy of this one
- Magna, Utah 2020 M 5.7 53,000× the energy of this one
- Around the size people start to feel M 3.0 4.7× the energy of this one
- This earthquake M 2.5 about 200 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 4.5 on 2019-10-15 — about 730 times the energy of this one.
Before 2016, the USGS record lists 5 earthquakes of M5 or more within 50 km:
- 6.0 The 2014 South Napa, California Earthquake · 40 km NW of this epicentre
- 5.8 The 1980 Livermore, California Earthquake · 24 km ESE of this epicentre
- 5.4 South of Elmira, California · 40 km NNE of this epicentre
- 5.4 9 km NE of Livermore, California · 34 km SE of this epicentre
- 5.1 11 km E of Blackhawk, California · 25 km SE 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 37.9513, -121.9963. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Contra Costa County, CA | 5 km (3 mi) | SE | earthquakes near Contra Costa County |
| Alameda County, CA | 35 km (22 mi) | SSE | earthquakes near Alameda County |
| Solano County, CA | 35 km (22 mi) | N | earthquakes near Solano County |
| San Joaquin County, CA | 64 km (39 mi) | E | earthquakes near San Joaquin County |
| Marin County, CA | 67 km (41 mi) | W | earthquakes near Marin County |
| Napa County, CA | 68 km (42 mi) | NNW | earthquakes near Napa County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
44 earthquakes have been recorded within 50 km since this one.
- 1.7 4 km NW of Orinda, CA
- 0.9 3 km ESE of Berkeley, CA
- 1.0 12 km SE of Livermore, CA
- 1.2 12 km SE of Livermore, CA
- 2.0 1 km NNW of East Richmond Heights, CA
- 1.7 2 km SW of San Ramon, CA
- 1.6 3 km SW of San Ramon, CA
- 1.1 8 km SSE of Sunol, CA
- 1.2 8 km SSE of Sunol, CA
- 2.3 4 km WNW of Orinda, CA
- 2.2 1 km E of Port Costa, CA
- 1.7 12 km SE of Livermore, CA
- 1.4 12 km SE of Livermore, CA
- 1.2 2 km E of Black Point-Green Point, CA
- 1.1 2 km NE of Danville, 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.