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 9:55 pm PST (05:55 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 31 km (19 mi) north-northwest of Santa Rosa, CA, at 6:22 am PDT on 19 September 2017 (13:22 UTC), 3.9 km deep. 1 person has reported feeling it to USGS.
USGS: 8 km E of Geyserville, California
30 km (19 mi) NNW of Santa Rosa, CA · 109 km (68 mi) NNW of San Francisco, CA
- When
- 6:22 am PDT on 19 September 2017 ()
- Where
- 31 km (19 mi) north-northwest of Santa Rosa, CA · earthquakes near Santa Rosa
- Magnitude
- M 2.1 (md)
- Depth
- 3.9 km below the surface
- Felt
- 1 report · strongest reported intensity II
- Nearest
- Sonoma County, 23 km SSW
- Nearest mapped fault
- Maacama 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 1558 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 17 km (11 mi) from the epicentre. In Santa Rosa, 31 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 13 km, intensity II · Cobb 14 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 43 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 5.8 350,000× the energy of this one
- Magna, Utah 2020 M 5.7 250,000× the energy of this one
- Around the size people start to feel M 3.0 22× the energy of this one
- This earthquake M 2.1 about 43 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 23,000 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 · 44 km S of this epicentre
- 5.3 Northern California · 43 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 38.7097, -122.8013. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Sonoma County, CA | 23 km (14 mi) | SSW | earthquakes near Sonoma County |
| Lake County, CA | 45 km (28 mi) | N | earthquakes near Lake County |
| Napa County, CA | 47 km (29 mi) | ESE | earthquakes near Napa County |
| Colusa County, CA | 71 km (44 mi) | NE | earthquakes near Colusa County |
| Marin County, CA | 73 km (46 mi) | S | earthquakes near Marin County |
| Yolo County, CA | 78 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
60 earthquakes have been recorded within 50 km since this one.
- 1.6 8 km WSW of Cobb, California
- 2.5 8 km WSW of Cobb, California
- 1.6 6 km W of Cobb, California
- 1.9 8 km WSW of Cobb, California
- 1.5 3 km WSW of Cobb, California
- 1.5 3 km W of Cobb, California
- 2.9 6 km W of Kenwood, California
- 1.5 Northern California
- 1.5 7 km W of Cobb, California
- 1.5 2 km W of Cobb, California
- 1.5 5 km SSW of Cobb, California
- 1.9 8 km ENE of Hidden Valley Lake, California
- 1.5 8 km W of Cobb, California
- 1.9 8 km W of Cobb, California
- 1.8 8 km W of Cobb, California
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.