Earthquake · reviewed by a seismologist
M 2.1md
Earthquake near Santa Rosa, CA
No earthquake was likely felt in Santa Rosa in the 24 hours to 3:53 pm PST (23:53 UTC). The last one was M 1.9, 5 km (3 mi) NE, at 2:01 pm PDT on 23 October 2026, estimated intensity II (weak) in town. Every earthquake near Santa Rosa
This page: a magnitude 2.1 earthquake was recorded 45 km (28 mi) north-northwest of Santa Rosa, CA, at 6:04 pm PDT on 31 October 2018 (01:04 UTC), 1.9 km deep.
USGS: 9km NW of The Geysers, CA
45 km (28 mi) NNW of Santa Rosa, CA · 123 km (76 mi) NNW of San Francisco, CA
- When
- 6:04 pm PDT on 31 October 2018 ()
- Where
- 45 km (28 mi) north-northwest of Santa Rosa, CA · earthquakes near Santa Rosa
- Magnitude
- M 2.1 (md)
- Depth
- 1.9 km below the surface
- Felt
- no reports yet
- Nearest
- Lake County, 31 km NNE
- Nearest mapped fault
- Konocti Bay fault, 10 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 2933 days ago
Earthquake alerts for Santa Rosa, CA
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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 18 km (11 mi) from the epicentre. In Santa Rosa, 45 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: Cobb 9 km, intensity II · Cloverdale 17 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 49 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.1 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 310,000× the energy of this one
- Magna, Utah 2020 M 5.7 220,000× the energy of this one
- Around the size people start to feel M 3.0 19× the energy of this one
- This earthquake M 2.1 about 49 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 20,000 times the energy of this one.
Before 2016, the USGS record lists one earthquake of M5 or more within 50 km:
- 5.2 6 km ESE of Talmage, California · 39 km NW 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 38.8362, -122.8245. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Lake County, CA | 31 km (19 mi) | NNE | earthquakes near Lake County |
| Sonoma County, CA | 36 km (22 mi) | SSW | earthquakes near Sonoma County |
| Napa County, CA | 57 km (35 mi) | SE | earthquakes near Napa County |
| Colusa County, CA | 63 km (39 mi) | NE | earthquakes near Colusa County |
| Yolo County, CA | 82 km (51 mi) | ESE | earthquakes near Yolo County |
| Mendocino County, CA | 85 km (53 mi) | NW | earthquakes near Mendocino 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.
- 1.8 5km SSE of The Geysers, CA
- 2.1 6km W of Cobb, CA
- 2.4 6km WNW of Cobb, CA
- 2.0 6km NNW of The Geysers, CA
- 1.7 10km SW of Kelseyville, CA
- 1.5 10km WNW of The Geysers, CA
- 1.8 9km NW of The Geysers, CA
- 1.8 6km NNW of The Geysers, CA
- 1.8 6km NNW of The Geysers, CA
- 1.6 7km WNW of The Geysers, CA
- 1.8 3km N of The Geysers, CA
- 1.5 7km NW of The Geysers, CA
- 1.6 3km W of Cobb, CA
- 1.9 6km NW of The Geysers, 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.