M4.8 earthquake 108 km W of Fortuna, California, United States
A magnitude 4.8 earthquake struck 108 km W of Fortuna, California, United States at 04:36 local time (11:36 UTC) on 29 Sept 2026, at a depth of 10 km, according to USGS and GFZ.
Reported by 2 agencies · revised from M4.5 · 16 reports to USGS “Did You Feel It?”
Data: USGS, GFZ · updated 2026-09-29 20:10 UTC · reviewed
- Magnitude
- 4.8light
moment magnitude (mw)
revised from 4.5 - Depth
- 10 km
- Status
- Reviewed
- Origin time
- 2026-09-29 11:36:39 UTC
- Local: 29 Sept 2026, 04:36:39 (America/Los Angeles)
- Epicentre
- 40.422° N, 125.418° W
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Circles show this event and others within 31 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 |
|---|---|---|
| FortunaCalifornia, United States · pop. 12,000 | 108 km | IIWeak |
| EurekaCalifornia, United States · pop. 27,017 | 114 km | IIWeak |
| San FranciscoCalifornia, United States · pop. 827,526 | 392 km | INot felt |
| SacramentoCalifornia, United States · pop. 524,943 | 394 km | INot felt |
| OaklandCalifornia, United States · pop. 419,267 | 398 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 99 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.
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How big was it?
Widely felt near the epicentre: rattling windows and objects. Significant damage is unlikely.
It released roughly the energy of 215 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 10 km this was a shallow earthquake, which is felt more strongly at the surface than a deeper one of the same size.
M4.8 releases about 29× the energy of M3.8, and its waves are about 9.3× taller on a seismogram. Energy: 215 t of TNT vs 7.6 t of TNT.
Each square is the energy of one M3.8. Energy from log₁₀E = 1.5M + 4.8.
Aftershocks and nearby activity
No later earthquakes have been recorded within 31 km so far. Aftershock rates usually fall off roughly in proportion to 1/time.
Did you feel it?
Reports from people help show where shaking was strong. They are anonymous and shown here in aggregate.
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Event id ew1790681810. First recorded here 29 Sept 2026, 11:37:45 UTC. Solutions: USGS · NC (usgs:nc75444322); GFZ (geofon:gfz2026tcai). Cite as: SeismoAtlas, “M4.8 earthquake 108 km W of Fortuna, California, United States”, https://seismoatlas.com/earthquake/ew1790681810-m4-8-earthquake-108-km-w-of-fortuna-california-united-states, data from USGS, GFZ.
JSON: /api/v1/events/ew1790681810. SeismoAtlas is not an official warning service.