QuakeIndex

Earthquake · reviewed by a seismologist

M 2.0md

Earthquake near Danville, CA

No earthquake was likely felt in Danville in the 24 hours to 9:03 am PST (17:03 UTC). The last one was M 2.6, 22 km (14 mi) WNW, at 6:23 pm PST on 1 November 2026, estimated intensity II (weak) in town; 114 felt reports to USGS. Every earthquake near Danville

This page: a magnitude 2.0 earthquake was recorded in Danville, CA, at 12:37 am PDT on 9 August 2017 (07:37 UTC), 9.4 km deep. 1 person has reported feeling it to USGS.

USGS: 1 km W of Danville, California

19 km (12 mi) ENE of Oakland, CA · 9 km (6 mi) S of Walnut Creek, CA

12:37 am PDT, Aug 9, 2017 · · 9.4 km deep · released about 31 lb of TNT

10 km30 km60 km120 km N Contra Costa County 13 kmAlameda County 21 kmSolano County 50 kmSan Mateo County 55 kmSan Joaquin County 67 kmMarin County 69 kmSanta Clara County 73 kmNapa County 81 kmSan Francisco County 89 km
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
12:37 am PDT on 9 August 2017 ()
Where
in Danville, CA · earthquakes near Danville
Magnitude
M 2.0 (md)
Depth
9.4 km below the surface
Felt
1 report · strongest reported intensity II
Nearest
Contra Costa County, 13 km NNE
Nearest mapped fault
Calaveras 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 3375 days ago

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 13 km (8 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: Danville in town, intensity II · Alamo 3 km, intensity II · San Ramon 6 km, intensity II · Walnut Creek 10 km, intensity II · Lafayette 11 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 31 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.0 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 480,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 340,000× the energy of this one
  3. Around the size people start to feel M 3.0 31× the energy of this one
  4. This earthquake M 2.0 about 31 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:

  1. 7.9 The 1906 San Francisco, California Earthquake · 47 km W of this epicentre
  2. 5.8 The 1980 Livermore, California Earthquake · 22 km E of this epicentre
  3. 5.7 15 km NE of East Foothills, California · 48 km SE of this epicentre
  4. 5.5 6 km NNE of East Foothills, California · 48 km SSE of this epicentre
  5. 5.4 9 km NE of Livermore, California · 29 km ESE 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 37.8198, -122.0218. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Contra Costa County, CA 13 km (8 mi) NNE earthquakes near Contra Costa County
Alameda County, CA 21 km (13 mi) SSE earthquakes near Alameda County
Solano County, CA 50 km (31 mi) N earthquakes near Solano County
San Mateo County, CA 55 km (34 mi) SW earthquakes near San Mateo County
San Joaquin County, CA 67 km (42 mi) E earthquakes near San Joaquin County
Marin County, CA 69 km (43 mi) WNW earthquakes near Marin County

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

59 earthquakes have been recorded within 50 km since this one.

  1. 1.7 1 km SSW of Clyde, California
  2. 1.7 1 km SW of Clyde, California
  3. 2.3 2 km WSW of Clyde, California
  4. 1.5 1 km SSE of Clyde, California
  5. 1.7 1 km WNW of Concord, California
  6. 1.9 3 km SE of Rodeo, California
  7. 1.7 7 km W of San Ramon, California
  8. 2.7 8 km SE of Livermore, California
  9. 1.9 7 km SE of Livermore, California
  10. 1.6 2 km ENE of Alameda, California
  11. 1.7 2 km E of Berkeley, California
  12. 1.5 2 km ESE of Berkeley, California
  13. 1.6 1 km NNW of Crockett, California
  14. 2.0 8 km NNE of East Foothills, California
  15. 1.8 Northern California

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

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.