QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7md

Earthquake near Ashland, CA

Yes. A magnitude 1.7 earthquake was recorded in Ashland, CA, at 4:04 pm PDT on 15 August 2016 (23:04 UTC), 5.5 km deep.

This was on 15 August 2016. The latest near Ashland: M 2.5 on 19 September 2026.

USGS: 1 km NNW of Ashland, California

11 km (7 mi) SE of Oakland, CA · in San Leandro, CA

4:04 pm PDT, Aug 15, 2016 · · 5.5 km deep · released about 10 lb of TNT

10 km30 km60 km120 km N Alameda County 19 kmContra Costa County 27 kmSan Mateo County 40 kmSolano County 64 kmSanta Clara County 66 kmMarin County 67 kmSanta Cruz County 78 kmSan Joaquin County 78 kmSan Francisco County 80 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
4:04 pm PDT on 15 August 2016 ()
Where
in Ashland, CA · earthquakes near Ashland
Magnitude
M 1.7 (md)
Depth
5.5 km below the surface
Felt
no reports yet
Nearest
Alameda County, 19 km ESE
Nearest mapped fault
Hayward 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 3532 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 11 km (7 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: Ashland in town, intensity II · Castro Valley 3 km, intensity II · San Leandro 4 km, intensity II · Cherryland 4 km, intensity II · San Lorenzo 4 km, intensity II · Hayward 6 km, intensity II · Fairview 7 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 10 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,500,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,100,000× the energy of this one
  3. Around the size people start to feel M 3.0 95× the energy of this one
  4. This earthquake M 1.7 about 10 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 8 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.9 The 1906 San Francisco, California Earthquake · 38 km W of this epicentre
  2. 5.8 The 1980 Livermore, California Earthquake · 34 km ENE of this epicentre
  3. 5.7 15 km NE of East Foothills, California · 46 km SE of this epicentre
  4. 5.5 6 km NNE of East Foothills, California · 43 km SE of this epicentre
  5. 5.4 9 km NE of Livermore, California · 37 km E 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 37.7105, -122.1188. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Alameda County, CA 19 km (12 mi) ESE earthquakes near Alameda County
Contra Costa County, CA 27 km (17 mi) NNE earthquakes near Contra Costa County
San Mateo County, CA 40 km (25 mi) SW earthquakes near San Mateo County
Solano County, CA 64 km (40 mi) NNE earthquakes near Solano County
Santa Clara County, CA 66 km (41 mi) SE earthquakes near Santa Clara County
Marin County, CA 67 km (42 mi) NW earthquakes near Marin County

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

Aftershocks so far

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

  1. 1.6 2 km S of Loyola, California
  2. 1.5 2 km N of Piedmont, California
  3. 2.1 6 km S of Sunol, California
  4. 2.2 7 km E of Blackhawk, California
  5. 1.8 10 km NW of Broadmoor, California
  6. 1.6 1 km ESE of Pacheco, California
  7. 1.5 5 km E of Alameda, California
  8. 1.5 5 km ENE of Chinatown, California
  9. 1.9 2 km ENE of Diablo, California
  10. 1.7 2 km S of Loyola, California
  11. 1.6 2 km SSW of Loyola, California
  12. 2.4 8 km NNE of East Foothills, California
  13. 1.6 5 km ESE of Piedmont, California
  14. 2.4 6 km WNW of Broadmoor, California
  15. 1.6 1 km NW of Ashland, 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.