Earthquake near Concord, CA

USGS: 0 km NE of North Gate, California

in Walnut Creek, CA · 40 km (25 mi) ENE of San Francisco, CA

7:23 am PDT, Oct 3, 2016 · 2016-10-03 14:23 UTC · 12 km deep · released about 60 lb of TNT

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Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.

When: 7:23 am PDT on 3 October 2016 (2016-10-03 14:23 UTC)
Where: 8 km (5 mi) SSE of Concord, CA · earthquakes near Concord
Magnitude: M 2.2 (md)
Depth: 12 km below the surface
Felt: 4 reports · strongest reported intensity II
Nearest: Contra Costa County, 4 km ENE
Nearest mapped fault: Greenville fault, 7 km from its surface trace — near is not the same as on
Status: Reviewed by a seismologist

USGS · last changed by USGS 3521 days ago · we first saw it 3521 days ago

A magnitude 2.2 earthquake was recorded 8 km (5 mi) SSE of Concord, CA, at 7:23 am PDT on 3 October 2016 (14:23 UTC). 4 people have reported feeling it to USGS. This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

Earthquakes near other towns within 30 km: Clayton, Waldon, Contra Costa Centre, Walnut Creek, Pleasant Hill, Acalanes Ridge.

How big was it?

This earthquake released about 60 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 5.8 250,000× the energy of this one
Magna, Utah 2020 M 5.7 180,000× the energy of this one
Around the size people start to feel M 3.0 16× the energy of this one
This earthquake M 2.2 about 60 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 5 earthquakes of M5 or more within 50 km:

6.0 The 2014 South Napa, California Earthquake · 44 km NW of this epicentre Aug 24, 2014
5.8 The 1980 Livermore, California Earthquake · 21 km ESE of this epicentre Jan 24, 1980
5.4 South of Elmira, California · 44 km N of this epicentre May 19, 1902
5.4 9 km NE of Livermore, California · 31 km SE of this epicentre Jan 27, 1980
5.1 11 km E of Blackhawk, California · 22 km ESE of this epicentre Jan 24, 1980

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

Map loads when it scrolls into view

Nearby places

Place	Distance	Direction from the epicentre
Contra Costa County, CA	4 km (2 mi)	ENE	earthquakes near Contra Costa County
Alameda County, CA	30 km (19 mi)	SSE	earthquakes near Alameda County
Solano County, CA	40 km (25 mi)	N	earthquakes near Solano County
San Joaquin County, CA	63 km (39 mi)	E	earthquakes near San Joaquin County
San Mateo County, CA	65 km (40 mi)	SSW	earthquakes near San Mateo County
Marin County, CA	68 km (42 mi)	WNW	earthquakes near Marin 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.

2.4 3 km ENE of Vallejo, California 23:10 UTC
1.8 2 km E of Berkeley, California 02:20 UTC
2.6 2 km SSW of Alamo, California 19:45 UTC
1.6 2 km ENE of San Leandro, California 19:13 UTC
1.7 1 km ENE of Alamo, California 07:22 UTC
1.8 3 km NNW of Castro Valley, California 07:18 UTC
2.1 3 km NNW of Castro Valley, California 04:34 UTC
1.8 2 km SSE of North Gate, California 01:03 UTC
1.9 3 km SE of North Gate, California 17:02 UTC
1.6 1 km SW of Blackhawk, California 12:11 UTC
2.1 0 km SW of Blackhawk, California 08:11 UTC
1.5 1 km SW of Blackhawk, California 07:54 UTC
2.4 2 km SSE of Berkeley, California 02:26 UTC
1.6 0 km SW of Blackhawk, California 01:37 UTC
1.9 1 km WSW of Concord, California 21:10 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 03:29 UTC. 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.