QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

15km E of Angwin, CA

· 7.7 km deep · released about 16 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Napa County 7 kmYolo County 36 kmSolano County 44 kmSonoma County 56 kmColusa County 69 kmMarin County 69 kmLake County 73 kmSutter County 73 kmContra Costa County 77 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
Magnitude
M 1.8 (md)
Depth
7.7 km below the surface
Felt
2 reports · strongest reported intensity II
Nearest
Napa County, 7 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1259 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 2 people have reported feeling it to USGS.

How big was it?

This earthquake released about 16 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 930,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 660,000× the energy of this one
  3. Around the size people start to feel M 3.0 59× the energy of this one
  4. This earthquake M 1.8 about 16 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.

Where

Epicentre 38.5593, -122.2837. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Napa County, CA 7 km (4 mi) NNE of here earthquakes near Napa County
Yolo County, CA 36 km (22 mi) WSW of here earthquakes near Yolo County
Solano County, CA 44 km (27 mi) NW of here earthquakes near Solano County
Sonoma County, CA 56 km (35 mi) E of here earthquakes near Sonoma County
Colusa County, CA 69 km (43 mi) S of here earthquakes near Colusa County
Marin County, CA 69 km (43 mi) NE of here earthquakes near Marin County

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

Aftershocks so far

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

  1. 1.5 1km WNW of The Geysers, CA
  2. 1.7 2km NW of The Geysers, CA
  3. 1.6 1km NNE of The Geysers, CA
  4. 2.4 0km NW of The Geysers, CA
  5. 2.2 4km SSE of Calistoga, CA
  6. 1.5 3km E of Penngrove, CA
  7. 1.7 2km SW of Anderson Springs, CA
  8. 2.2 7km SSW of Calistoga, CA
  9. 1.5 2km NW of The Geysers, CA
  10. 1.6 11km E of Hidden Valley Lake, CA
  11. 1.6 3km W of Anderson Springs, CA
  12. 1.6 2km WSW of Anderson Springs, CA
  13. 1.6 1km NW of The Geysers, CA
  14. 1.7 2km NNW of The Geysers, CA
  15. 1.7 1km NW of The Geysers, 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.

For this area

The largest earthquake within 50 km in our catalogue was M 4.4 on 2022-09-14 — it released about 7,200 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

On USGS

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