QuakeIndex

Earthquake · reviewed by a seismologist

M 1.9md

Earthquake near Orinda, CA

No earthquake was likely felt in Orinda in the 24 hours to 9:11 am PST (17:11 UTC). The last one was M 2.1, 12 km (8 mi) NE, at 4:05 am PST on 8 November 2026, estimated intensity II (weak) in town; 3 felt reports to USGS. Every earthquake near Orinda

This page: a magnitude 1.9 earthquake was recorded 3 km (2 mi) northeast of Orinda, CA, at 2:14 pm PDT on 24 September 2019 (21:14 UTC), 6.4 km deep. 3 people have reported feeling it to USGS.

USGS: 3km NE of Orinda, CA

26 km (16 mi) ENE of San Francisco, CA · 11 km (7 mi) W of Walnut Creek, CA

2:14 pm PDT, Sep 24, 2019 · · 6.4 km deep · released about 19 lb of TNT

10 km30 km60 km120 km N Contra Costa County 18 kmAlameda County 35 kmSolano County 46 kmMarin County 54 kmSan Mateo County 57 kmNapa County 70 kmSan Joaquin County 78 kmSan Francisco County 79 kmSanta Clara County 86 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
2:14 pm PDT on 24 September 2019 ()
Where
3 km (2 mi) northeast of Orinda, CA · earthquakes near Orinda
Magnitude
M 1.9 (md)
Depth
6.4 km below the surface
Felt
3 reports · strongest reported intensity II
Nearest
Contra Costa County, 18 km E
Nearest mapped fault
Hayward fault, 8 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 2597 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. In Orinda, 3 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: Orinda 3 km, intensity II · Lafayette 4 km, intensity II · Walnut Creek 8 km, intensity II · Berkeley 10 km, intensity II · Pleasant Hill 11 km, intensity II · Alamo 12 km, intensity II · Pacheco 12 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 19 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 810,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 580,000× the energy of this one
  3. Around the size people start to feel M 3.0 51× the energy of this one
  4. This earthquake M 1.9 about 19 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 6,000 times the energy of this one.

Before 2016, the USGS record lists 6 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.9 The 1906 San Francisco, California Earthquake · 38 km WSW of this epicentre
  2. 6.0 The 2014 South Napa, California Earthquake · 38 km NNW of this epicentre
  3. 5.8 The 1980 Livermore, California Earthquake · 35 km E of this epicentre
  4. 5.4 9 km NE of Livermore, California · 43 km ESE of this epicentre
  5. 5.3 The 1957 San Francisco, California Earthquake · 38 km SW 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 37.8947, -122.1600. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Contra Costa County, CA 18 km (11 mi) E earthquakes near Contra Costa County
Alameda County, CA 35 km (22 mi) SE earthquakes near Alameda County
Solano County, CA 46 km (28 mi) NNE earthquakes near Solano County
Marin County, CA 54 km (34 mi) WNW earthquakes near Marin County
San Mateo County, CA 57 km (35 mi) SSW earthquakes near San Mateo County
Napa County, CA 70 km (43 mi) NNW earthquakes near Napa 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. 1.6 8km E of Sunol, CA
  2. 1.8 4km W of Dublin, CA
  3. 1.7 3km ENE of Pacheco, CA
  4. 1.8 7km SSW of Muir Beach, CA
  5. 2.2 3km NNW of Pacifica, CA
  6. 1.9 5km NNW of Pittsburg, CA
  7. 1.7 4km NNE of Dublin, CA
  8. 2.7 4km N of Dublin, CA
  9. 1.6 6km WNW of Dublin, CA
  10. 2.4 6km N of Diablo, CA
  11. 1.5 6km SSE of Byron, CA
  12. 1.7 2km NE of Union City, CA
  13. 1.6 1km WNW of Pleasant Hill, CA
  14. 3.2 0km WNW of Pleasant Hill, CA
  15. 1.8 1km NW of Pleasant Hill, 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

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