Earthquake · reviewed by a seismologist
M 2.1md
Earthquake near Challenge-Brownsville, CA
No earthquake was likely felt in Challenge-Brownsville in the 24 hours to 11:17 am PST (19:17 UTC). The last one was M 2.0, 6 km (4 mi) E, at 11:19 pm PDT on 31 August 2026, estimated intensity II (weak) in town. Every earthquake near Challenge-Brownsville
This page: a magnitude 2.1 earthquake was recorded 7 km (4 mi) east-southeast of Challenge-Brownsville, CA, at 11:29 pm PDT on 23 July 2026 (06:29 UTC), 14 km deep.
USGS: 7 km ESE of Challenge-Brownsville, CA
100 km (62 mi) NNE of Sacramento, CA · 52 km (32 mi) NE of Yuba City, CA
- When
- 11:29 pm PDT on 23 July 2026 ()
- Where
- 7 km (4 mi) east-southeast of Challenge-Brownsville, CA · earthquakes near Challenge-Brownsville
- Magnitude
- M 2.1 (md)
- Depth
- 14 km below the surface
- Felt
- no reports yet
- Nearest
- Yuba County, 23 km SW
- Nearest mapped fault
- Foothills fault system, 20 km from its surface trace — near is not the same as on
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 102 days ago
Earthquake alerts for Challenge-Brownsville, CA
Get a notification in this browser when USGS records an earthquake near Challenge-Brownsville, CA. No account or email needed.
Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.
At this magnitude and depth, people at rest would likely notice it out to about 10 km (6 mi) from the epicentre. In Challenge-Brownsville, 7 km away, the estimate is intensity II (weak). Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.
Earthquakes near other towns within 30 km: Lake Wildwood, Loma Rica, Nevada City, Oroville East, Grass Valley, Penn Valley.
How big was it?
This earthquake released about 40 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 5.8 380,000× the energy of this one
- Magna, Utah 2020 M 5.7 270,000× the energy of this one
- Around the size people start to feel M 3.0 24× the energy of this one
- This earthquake M 2.1 about 40 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 4.2 on 2022-07-23 — about 1,700 times the energy of this one.
Before 2016, the USGS record lists 5 earthquakes of M5 or more within 50 km:
- 5.9 West of Downieville, California · 18 km ENE of this epicentre
- 5.7 The 1975 Oroville, California Earthquake · 31 km W of this epicentre
- 5.2 4 km E of Palermo, California · 26 km W of this epicentre
- 5.1 5 km ENE of Palermo, California · 25 km W of this epicentre
- 5.0 Nevada County, California · 25 km E 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 39.4382, -121.1875. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Yuba County, CA | 23 km (14 mi) | SW | earthquakes near Yuba County |
| Nevada County, CA | 39 km (24 mi) | ESE | earthquakes near Nevada County |
| Butte County, CA | 44 km (27 mi) | NW | earthquakes near Butte County |
| Placer County, CA | 58 km (36 mi) | SE | earthquakes near Placer County |
| Sierra County, CA | 59 km (37 mi) | ENE | earthquakes near Sierra County |
| Sutter County, CA | 63 km (39 mi) | SW | earthquakes near Sutter County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
2 earthquakes have been recorded within 50 km since this one.
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.