Earthquake · reviewed by a seismologist
M 1.5md
Earthquake near Cobb, CA
Yes: an earthquake was likely felt in Cobb in the last 24 hours. M 1.6, 4 km (2 mi) W of Cobb, at 1:30 pm PST on 11 November 2026 (21:30 UTC); the estimated shaking in Cobb was intensity II (weak). Every earthquake near Cobb
This page: a magnitude 1.5 earthquake was recorded 8 km (5 mi) west-southwest of Cobb, CA, at 12:19 pm PST on 27 February 2017 (20:19 UTC), 3.3 km deep.
USGS: 8 km WSW of Cobb, California
41 km (25 mi) NNW of Santa Rosa, CA · 119 km (74 mi) NNW of San Francisco, CA
- When
- 12:19 pm PST on 27 February 2017 ()
- Where
- 8 km (5 mi) west-southwest of Cobb, CA · earthquakes near Cobb
- Magnitude
- M 1.5 (md)
- Depth
- 3.3 km below the surface
- Felt
- no reports yet
- Nearest
- Sonoma County, 32 km SSW
- Nearest mapped fault
- Maacama fault, 11 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 3541 days ago
Earthquake alerts for Cobb, CA
Get a notification in this browser when USGS records an earthquake near Cobb, 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 9 km (6 mi) from the epicentre. In Cobb, 8 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 8 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 5.4 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.
- Mineral, Virginia 2011 M 5.8 2,800,000× the energy of this one
- Magna, Utah 2020 M 5.7 2,000,000× the energy of this one
- Around the size people start to feel M 3.0 180× the energy of this one
- This earthquake M 1.5 about 5.4 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 180,000 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 · 42 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 38.8035, -122.8147. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Sonoma County, CA | 32 km (20 mi) | SSW | earthquakes near Sonoma County |
| Lake County, CA | 34 km (21 mi) | N | earthquakes near Lake County |
| Napa County, CA | 54 km (33 mi) | SE | earthquakes near Napa County |
| Colusa County, CA | 65 km (40 mi) | NE | earthquakes near Colusa County |
| Yolo County, CA | 80 km (50 mi) | E | earthquakes near Yolo County |
| Marin County, CA | 84 km (52 mi) | S | earthquakes near Marin County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
56 earthquakes have been recorded within 50 km since this one.
- 1.7 5 km WSW of Cobb, California
- 1.5 6 km S of Cobb, California
- 1.9 4 km WNW of Cobb, California
- 1.6 9 km W of Cobb, California
- 1.9 9 km W of Cobb, California
- 1.7 Northern California
- 1.8 7 km S of Cobb, California
- 1.5 2 km SW of Cobb, California
- 1.7 5 km WNW of Cobb, California
- 2.8 4 km W of Cobb, California
- 1.6 6 km W of Cobb, California
- 1.8 9 km W of Cobb, California
- 1.8 8 km WSW of Cobb, California
- 2.0 8 km WSW of Cobb, California
- 1.5 7 km WSW 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.