QuakeIndex

Earthquake · reviewed by a seismologist

M 1.5md

Earthquake near Clearlake, CA

No earthquake was likely felt in Clearlake in the 24 hours to 5:44 am PST (13:44 UTC). The last one was M 2.6, 22 km (14 mi) SSW, at 4:44 pm PST on 8 November 2026, estimated intensity II (weak) in town. Every earthquake near Clearlake

This page: a magnitude 1.5 earthquake was recorded 10 km (6 mi) east-northeast of Clearlake, CA, at 7:17 am PDT on 28 April 2021 (14:17 UTC), 2.9 km deep.

USGS: 10km ENE of Clearlake, CA

7:17 am PDT, Apr 28, 2021 · · 2.9 km deep · released about 5.9 lb of TNT

10 km30 km60 km120 km N Lake County 24 kmColusa County 32 kmNapa County 56 kmSonoma County 63 kmYolo County 63 kmGlenn County 69 kmSutter County 70 kmMendocino County 94 kmSolano County 95 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
7:17 am PDT on 28 April 2021 ()
Where
10 km (6 mi) east-northeast of Clearlake, CA · earthquakes near Clearlake
Magnitude
M 1.5 (md)
Depth
2.9 km below the surface
Felt
no reports yet
Nearest
Lake County, 24 km WNW
Nearest mapped fault
Hunting Creek-Berryessa fault system, 2 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 2022 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 10 km (6 mi) from the epicentre. In Clearlake, 10 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.

Earthquakes near other towns within 30 km: Lower Lake, Clearlake Oaks, Clear Lake Riviera, Hidden Valley Lake, Soda Bay, Cobb.

How big was it?

This earthquake released about 5.9 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,500,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,800,000× the energy of this one
  3. Around the size people start to feel M 3.0 160× the energy of this one
  4. This earthquake M 1.5 about 5.9 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 5.1 on 2016-08-10 — about 220,000 times the energy of this one.

Before 2016, the USGS record since 1900 lists no earthquake of M5 or more within 50 km.

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 38.9920, -122.5142. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Lake County, CA 24 km (15 mi) WNW earthquakes near Lake County
Colusa County, CA 32 km (20 mi) NE earthquakes near Colusa County
Napa County, CA 56 km (35 mi) SSE earthquakes near Napa County
Sonoma County, CA 63 km (39 mi) SW earthquakes near Sonoma County
Yolo County, CA 63 km (39 mi) ESE earthquakes near Yolo County
Glenn County, CA 69 km (43 mi) N earthquakes near Glenn County

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

Aftershocks so far

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

  1. 1.9 8km WNW of Cobb, CA
  2. 1.8 4km NW of The Geysers, CA
  3. 1.9 11km WNW of The Geysers, CA
  4. 1.5 13km ESE of Hidden Valley Lake, CA
  5. 2.1 7km WNW of Cobb, CA
  6. 1.5 14km E of Lower Lake, CA
  7. 2.0 6km NW of The Geysers, CA
  8. 1.7 6km NW of The Geysers, CA
  9. 1.7 6km NW of The Geysers, CA
  10. 1.8 3km NE of The Geysers, CA
  11. 1.7 14km NNE of Angwin, CA
  12. 1.6 15km NNE of Angwin, CA
  13. 2.0 15km NNE of Angwin, CA
  14. 2.2 15km NNE of Angwin, CA
  15. 1.6 10km WNW 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.

On USGS

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