Earthquake · automatic estimate, may change
M 1.3md
Earthquake near Cobb, CA
USGS: 3 km S of Cobb, CA
39 km (24 mi) N of Santa Rosa, CA · 116 km (72 mi) NNW of San Francisco, CA
- When
- 11:56 am PDT on 29 September 2026 ()
- Where
- 3 km (2 mi) S of Cobb, CA · earthquakes near Cobb
- Magnitude
- M 1.3 (md)
- Depth
- 1.9 km below the surface
- Felt
- no reports yet
- Nearest
- Sonoma County, 35 km SSW
- Nearest mapped fault
- Konocti Bay fault, 10 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 3 days ago
A magnitude 1.3 earthquake was recorded 3 km (2 mi) S of Cobb, CA, at 11:56 am PDT on 29 September 2026 (18:56 UTC). This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.
Earthquakes near other towns within 30 km: Middletown, Hidden Valley Lake, Lower Lake, Clear Lake Riviera, Clearlake, Kelseyville.
How big was it?
This earthquake released about 2.4 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.3 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 6,200,000× the energy of this one
- Magna, Utah 2020 M 5.7 4,400,000× the energy of this one
- Around the size people start to feel M 3.0 390× the energy of this one
- This earthquake M 1.3 about 2.4 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 410,000 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 · 48 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 38.7958, -122.7287. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Sonoma County, CA | 35 km (22 mi) | SSW | earthquakes near Sonoma County |
| Lake County, CA | 35 km (22 mi) | N | earthquakes near Lake County |
| Napa County, CA | 47 km (30 mi) | SE | earthquakes near Napa County |
| Colusa County, CA | 60 km (37 mi) | NE | earthquakes near Colusa County |
| Yolo County, CA | 73 km (45 mi) | E | earthquakes near Yolo County |
| Marin County, CA | 83 km (51 mi) | S | earthquakes near Marin 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.
- 0.8 8 km WNW of Cobb, CA
- 1.3 8 km ESE of Cloverdale, CA
- 1.1 8 km W of Cobb, CA
- 0.7 8 km W of Cobb, CA
- 0.7 8 km W of Cobb, CA
- 1.4 8 km W of Cobb, CA
- 1.9 8 km W of Cobb, CA
- 0.7 5 km NNW of The Geysers, CA
- 1.8 4 km NW of Santa Rosa, CA
- 0.5 6 km NW of The Geysers, CA
- 1.0 2 km WSW of Anderson Springs, CA
- 1.2 10 km WNW of The Geysers, CA
- 1.7 3 km SSW of Anderson Springs, CA
- 1.2 8 km W of Cobb, CA
- 1.2 10 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.