M4.7 earthquake 111 km W of Fortuna, California, United States

Name: M4.7 earthquake 111 km W of Fortuna, California, United States
Start: 2026-09-29T11:36:37.910Z
End: 2026-09-29T11:36:37.910Z
Location: 111 km W of Fortuna, California, United States

A magnitude 4.7 earthquake struck 111 km W of Fortuna, California, United States at 04:36 local time (11:36 UTC) on 29 Sept 2026, at a depth of 2 km, according to USGS and GFZ.

Reported by 2 agencies · revised from M4.5 · 1 reports to USGS “Did You Feel It?”

Data: USGS, GFZ · updated 2026-09-29 11:49 UTC · reviewed

Magnitude: 4.7light
moment magnitude (mw)
revised from 4.5
Depth: 2.3 km
Status: Reviewed
Origin time: 2026-09-29 11:36:37 UTC; Local: 29 Sept 2026, 04:36:37 (America/Los Angeles)
Epicentre: 40.433° N, 125.460° 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

Distance and estimated shaking at nearby places
Place	Distance	Est. shaking
FortunaCalifornia, United States · pop. 12,000	111 km	IIWeak
EurekaCalifornia, United States · pop. 27,017	117 km	IIWeak
San FranciscoCalifornia, United States · pop. 827,526	396 km	INot felt
SacramentoCalifornia, United States · pop. 524,943	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 95 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	4.7 mwwas 4.3	2.3 km	40.43° N, 125.46° W	–	Reviewed · 3 revisions
GFZGFZ via GEOFON, GFZ Helmholtz Centre for Geosciences	4.7 mb	10 km	40.60° N, 125.25° W	+5.4 s	Automatic

How big was it?

Widely felt near the epicentre: rattling windows and objects. Significant damage is unlikely.

It released roughly the energy of 188 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 2 km this was a shallow earthquake, which is felt more strongly at the surface than a deeper one of the same size.

Compare M4.7 with M3.7

M4.7 releases about 35× the energy of M3.7, and its waves are about 11× taller on a seismogram. Energy: 188 t of TNT vs 5.4 t of TNT.

Each square is the energy of one M3.7. Energy from log₁₀E = 1.5M + 4.8.

Aftershocks and nearby activity

No later earthquakes have been recorded within 30 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.

Reports on SeismoAtlas

No reports yet.

USGS “Did You Feel It?” has 1 reports: add yours at USGS.

Event id ew1790681810. First recorded here 29 Sept 2026, 11:37:45 UTC. Solutions: USGS · NC (usgs:nc75444322); GFZ (geofon:gfz2026tcai). Cite as: SeismoAtlas, “M4.7 earthquake 111 km W of Fortuna, California, United States”, https://seismoatlas.com/earthquake/ew1790681810-m4-7-earthquake-111-km-w-of-fortuna-california-united-states, data from USGS, GFZ.

JSON: /api/v1/events/ew1790681810. SeismoAtlas is not an official warning service.