M3.7 earthquake 28 km WSW of Ukiah, California, United States
A magnitude 3.7 earthquake struck 28 km WSW of Ukiah, California, United States at 20:42 local time (03:42 UTC) on 25 Sept 2026, at a depth of 5 km, according to USGS.
134 reports to USGS “Did You Feel It?”
Data: USGS · updated 2026-09-27 13:52 UTC · reviewed
- Magnitude
- 3.7minor
moment magnitude (mw) - Depth
- 4.8 km
- Status
- Reviewed
- Origin time
- 2026-09-26 03:42:49 UTC
- Local: 25 Sept 2026, 20:42:49 (America/Los Angeles)
- Epicentre
- 39.014° N, 123.477° W
Circles show this event and others within 30 km from 7 days before to 30 days after. Lines: plate boundaries and GEM active faults. Open on the live map
Nearby places
| Place | Distance | Est. shaking |
|---|---|---|
| UkiahCalifornia, United States · pop. 15,917 | 28 km | IIIWeak |
| CloverdaleCalifornia, United States · pop. 8,811 | 46 km | IIWeak |
| WindsorCalifornia, United States · pop. 27,464 | 77 km | INot felt |
| Santa RosaCalifornia, United States · pop. 178,127 | 92 km | INot felt |
| Rohnert ParkCalifornia, United States · pop. 42,407 | 101 km | INot felt |
| PetalumaCalifornia, United States · pop. 60,438 | 114 km | INot felt |
| San FranciscoCalifornia, United States · pop. 827,526 | 166 km | INot felt |
| OaklandCalifornia, United States · pop. 419,267 | 171 km | INot felt |
Shaking is an estimate from the intensity prediction equation of Allen, Wald & Worden (2012), not an observation. Local ground and buildings can change it by a level or more. Likely felt out to about 33 km.
Every agency's solution
Agencies locate earthquakes with their own stations and methods, so their numbers differ. We match reports of the same event by time, distance and magnitude and show them side by side. The headline uses USGS · NC, which has been reviewed by an analyst.
| Agency | Magnitude | Depth | Epicentre | Time offset | Status |
|---|---|---|---|---|---|
| USGS · NCheadlineNorthern California Seismic System via U.S. Geological Survey | 3.7 mw | 4.8 km | 39.01° N, 123.48° W | – | Reviewed |
How big was it?
Often felt by people at rest close to the epicentre, rarely causes damage.
It released roughly the energy of 6.1 t of TNT. Magnitude is logarithmic: each whole step means about 32 times more energy and 10 times larger waves on a seismogram. Depth matters too: at 5 km this was a shallow earthquake, which is felt more strongly at the surface than a deeper one of the same size.
M3.7 releases about 36× the energy of M2.7, and its waves are about 11× taller on a seismogram. Energy: 6.1 t of TNT vs 169 kg of TNT.
Each square is the energy of one M2.7. Energy from log₁₀E = 1.5M + 4.8.
Aftershocks and nearby activity
4 later earthquakes within 30 km; the largest was M2.7 2 days ago. Aftershock rates usually fall off roughly in proportion to 1/time.
Mainshock M3.7
4 later earthquakes nearby. Aftershock rates typically fall off roughly as 1/time (Omori's law).
| Time after mainshock (hours) | Magnitude | Depth (km) |
|---|---|---|
| 0.32 | 2.7 | 3 |
| 0.54 | 1.8 | 2 |
| 23.09 | 1.7 | 1 |
| 64.56 | 2.1 | 2 |
Did you feel it?
Reports from people help show where shaking was strong. They are anonymous and shown here in aggregate.
Event id nc75442207. First recorded here 28 Sept 2026, 17:32:09 UTC. Solutions: USGS · NC (usgs:nc75442207). Cite as: SeismoAtlas, “M3.7 earthquake 28 km WSW of Ukiah, California, United States”, https://seismoatlas.com/earthquake/nc75442207-m3-7-earthquake-28-km-wsw-of-ukiah-california-united-states, data from USGS.
JSON: /api/v1/events/nc75442207. SeismoAtlas is not an official warning service.