QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6md

Earthquake near Healdsburg, CA

No earthquake was likely felt in Healdsburg in the 24 hours to 11:34 pm PST (07:34 UTC). The last one was M 2.6, 22 km (14 mi) NNE, at 4:44 pm PST on 8 November 2026, estimated intensity II (weak) in town. Every earthquake near Healdsburg

This page: a magnitude 1.6 earthquake was recorded 7 km (4 mi) northeast of Healdsburg, CA, at 4:40 pm PST on 16 February 2024 (00:40 UTC), 7.3 km deep.

USGS: 7 km NE of Healdsburg, CA

25 km (15 mi) NNW of Santa Rosa, CA · 103 km (64 mi) NNW of San Francisco, CA

4:40 pm PST, Feb 16, 2024 · · 7.3 km deep · released about 6.6 lb of TNT

10 km30 km60 km120 km N Sonoma County 17 kmNapa County 45 kmLake County 51 kmMarin County 67 kmColusa County 77 kmYolo County 79 kmSolano County 87 kmMendocino County 103 kmSan Francisco County 104 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
4:40 pm PST on 16 February 2024 ()
Where
7 km (4 mi) northeast of Healdsburg, CA · earthquakes near Healdsburg
Magnitude
M 1.6 (md)
Depth
7.3 km below the surface
Felt
no reports yet
Nearest
Sonoma County, 17 km SW
Nearest mapped fault
Alexander-Redwood Hill fault, 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 993 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 8 km (5 mi) from the epicentre. In Healdsburg, 7 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: Healdsburg 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 6.6 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,300,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,600,000× the energy of this one
  3. Around the size people start to feel M 3.0 140× the energy of this one
  4. This earthquake M 1.6 about 6.6 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 5.0 on 2016-12-14 — about 150,000 times the energy of this one.

Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:

  1. 5.3 3 km E of Bloomfield, California · 37 km S of this epicentre
  2. 5.3 Northern California · 37 km S 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 38.6510, -122.8128. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Sonoma County, CA 17 km (11 mi) SW earthquakes near Sonoma County
Napa County, CA 45 km (28 mi) ESE earthquakes near Napa County
Lake County, CA 51 km (32 mi) N earthquakes near Lake County
Marin County, CA 67 km (42 mi) S earthquakes near Marin County
Colusa County, CA 77 km (48 mi) NE earthquakes near Colusa County
Yolo County, CA 79 km (49 mi) E earthquakes near Yolo 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. 2.3 7 km WNW of Cobb, CA
  2. 2.2 6 km WNW of The Geysers, CA
  3. 1.6 7 km W of Cobb, CA
  4. 1.8 6 km W of Cobb, CA
  5. 2.2 3 km W of Anderson Springs, CA
  6. 1.5 3 km S of Cobb, CA
  7. 2.1 10 km WNW of The Geysers, CA
  8. 1.7 4 km WNW of Cobb, CA
  9. 1.5 2 km ESE of The Geysers, CA
  10. 1.7 4 km NW of The Geysers, CA
  11. 2.3 8 km NW of The Geysers, CA
  12. 1.8 7 km W of Cobb, CA
  13. 1.9 6 km W of Glen Ellen, CA
  14. 2.1 2 km ESE of The Geysers, CA
  15. 1.7 4 km NNW 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.