Earthquake · reviewed by a seismologist
M 1.8md
Earthquake near Windsor, CA
No earthquake was likely felt in Windsor in the 24 hours to 12:49 am PST (08:49 UTC). The last one was M 3.0, 30 km (18 mi) N, at 11:06 pm PDT on 14 October 2026, estimated intensity II (weak) in town; 1 felt report to USGS. Every earthquake near Windsor
This page: a magnitude 1.8 earthquake was recorded 4 km (3 mi) north-northeast of Windsor, CA, at 2:08 am PDT on 18 August 2018 (09:08 UTC), 11 km deep.
USGS: 4km NNE of Windsor, CA
18 km (11 mi) NNW of Santa Rosa, CA
- When
- 2:08 am PDT on 18 August 2018 ()
- Where
- 4 km (3 mi) north-northeast of Windsor, CA · earthquakes near Windsor
- Magnitude
- M 1.8 (md)
- Depth
- 11 km below the surface
- Felt
- no reports yet
- Nearest
- Sonoma County, 13 km WSW
- Nearest mapped fault
- Rodgers Creek 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 3005 days ago
Earthquake alerts for Windsor, CA
Get a notification in this browser when USGS records an earthquake near Windsor, CA. No account or email needed.
Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
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 Windsor, 4 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: Windsor 4 km, intensity II · Healdsburg 6 km, intensity II. Estimated for each town centre; each link is that town's own record.
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.
- Mineral, Virginia 2011 M 5.8 970,000× the energy of this one
- Magna, Utah 2020 M 5.7 680,000× the energy of this one
- Around the size people start to feel M 3.0 61× the energy of this one
- 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.
For this area
The largest earthquake within 50 km since 2016 was M 5.0 on 2016-12-14 — about 63,000 times the energy of this one.
Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:
- 5.3 3 km E of Bloomfield, California · 30 km S of this epicentre
- 5.3 Northern California · 29 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 38.5853, -122.8028. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Sonoma County, CA | 13 km (8 mi) | WSW | earthquakes near Sonoma County |
| Napa County, CA | 42 km (26 mi) | ESE | earthquakes near Napa County |
| Lake County, CA | 58 km (36 mi) | N | earthquakes near Lake County |
| Marin County, CA | 60 km (37 mi) | S | earthquakes near Marin County |
| Yolo County, CA | 79 km (49 mi) | E | earthquakes near Yolo County |
| Colusa County, CA | 82 km (51 mi) | NE | earthquakes near Colusa 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.
- 1.9 1km ESE of The Geysers, CA
- 1.6 2km WNW of Cobb, CA
- 1.9 5km NNW of The Geysers, CA
- 2.0 5km NNW of The Geysers, CA
- 1.6 9km WNW of The Geysers, CA
- 1.9 2km ENE of The Geysers, CA
- 1.7 9km NW of The Geysers, CA
- 1.8 6km WNW of Cobb, CA
- 1.8 15km E of Angwin, CA
- 1.6 6km E of Hidden Valley Lake, CA
- 1.9 9km WNW of Cobb, CA
- 1.9 7km WNW of The Geysers, CA
- 1.5 2km NW of The Geysers, CA
- 2.1 6km NE of Penngrove, CA
- 1.9 6km 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.
On USGS
- The official USGS event page — the source of record for every value above
- Did you feel it? Report it to USGS — reports go to USGS, not to us
- ShakeMap for this event, when USGS has produced one
QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.