Earthquake · automatic estimate, may change
M 2.1md
Earthquake near Cobb, CA
USGS: 10 km WNW of Cobb, CA
46 km (29 mi) NNW of Santa Rosa, CA · 124 km (77 mi) NNW of San Francisco, CA
- When
- 1:20 pm PDT on 28 September 2026 ()
- Where
- 10 km (6 mi) WNW of Cobb, CA · earthquakes near Cobb
- Magnitude
- M 2.1 (md)
- Depth
- 0.6 km below the surface
- Felt
- no reports yet
- Nearest
- Lake County, 30 km NNE
- Nearest mapped fault
- Konocti Bay fault, 11 km from its surface trace — near is not the same as on
- Status
- Automatic — a machine’s first estimate, which may change
USGS · last changed by USGS · we first saw it 4 days ago
A magnitude 2.1 earthquake was recorded 10 km (6 mi) WNW of Cobb, CA, at 1:20 pm PDT on 28 September 2026 (20:20 UTC). This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.
Earthquakes near other towns within 30 km: Kelseyville, Clear Lake Riviera, Cloverdale, Soda Bay, Lower Lake, Clearlake.
How big was it?
This earthquake released about 37 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 5.8 410,000× the energy of this one
- Magna, Utah 2020 M 5.7 290,000× the energy of this one
- Around the size people start to feel M 3.0 26× the energy of this one
- This earthquake M 2.1 about 37 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 27,000 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 · 37 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 38.8487, -122.8373. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Lake County, CA | 30 km (19 mi) | NNE | earthquakes near Lake County |
| Sonoma County, CA | 37 km (23 mi) | SSW | earthquakes near Sonoma County |
| Napa County, CA | 58 km (36 mi) | SE | earthquakes near Napa County |
| Colusa County, CA | 63 km (39 mi) | NE | earthquakes near Colusa County |
| Yolo County, CA | 83 km (52 mi) | ESE | earthquakes near Yolo County |
| Mendocino County, CA | 83 km (52 mi) | NW | earthquakes near Mendocino County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
58 earthquakes have been recorded within 50 km since this one.
- 1.1 3 km E of The Geysers, CA
- 1.1 7 km NW of The Geysers, CA
- 1.1 7 km NW of The Geysers, CA
- 1.3 8 km W of Cobb, CA
- 1.7 8 km ESE of Cloverdale, CA
- 0.4 10 km NW of The Geysers, CA
- 0.4 5 km WNW of Cobb, CA
- 1.3 5 km W of Cobb, CA
- 1.0 8 km NW of The Geysers, CA
- 1.1 4 km SW of Anderson Springs, CA
- 1.3 3 km NNW of The Geysers, CA
- 1.3 5 km WNW of The Geysers, CA
- 1.1 5 km WNW of The Geysers, CA
- 0.9 8 km WNW of Cobb, CA
- 1.1 5 km WNW 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.