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United States · California

M2.3 Earthquake near Contra Costa County, California (United States)

UTC time: 2026-09-26 17:41:27 UTC Local time: —
Magnitude
M2.3
Depth
3.9 km
Source
USGS

California · Contra Costa County

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About this earthquake

A magnitude M2.3 earthquake was recorded near Contra Costa County, California (United States) on September 26, 2026 at 17:41 UTC. The hypocenter lay relatively close to the surface at around 4 km, increasing how strongly it was felt. Earthquakes of this small magnitude are usually barely noticeable and cause no damage.

The data is provided by USGS and cross-checked across seismological networks. United States: 157 earthquakes were recorded in the past 24 hours, the strongest reaching M3.9.

Depth profile

Depth profile Depth: 3.9 km (Shallow) Surface Shallow Intermediate Deep 0 km 70 km 300 km 700 km 3.9 km
Shallow
3.9 km
3.9 km — shallower than the regional average (15.2 km)
Regional average: 15.2 km
Why depth matters

Shallow quakes release energy near the surface — shaking is felt more strongly and damage potential is higher.

Depth classes per USGS

Volcanoes nearby

  • Clear Lake Volcanic Field
    Distance: 129 km ·Volcanic field ·Elevation: 1'439 m ·United States
  • Mono Lake Volcanic Field
    Distance: 280 km ·Volcanic field ·Elevation: 2'121 m ·Last eruption: 1790 ·United States
  • Mono-Inyo Craters
    Distance: 281 km ·Lava dome(s) ·Elevation: 2'796 m ·Last eruption: 1380 ·United States
  • Mammoth Mountain
    Distance: 282 km ·Lava dome(s) ·Elevation: 3'369 m ·Last eruption: 1260 ·United States
  • Lassen Volcanic Center
    Distance: 296 km ·Stratovolcano ·Elevation: 3'187 m ·Last eruption: 1917 ·United States
  • Soda Lakes
    Distance: 343 km ·Maar(s) ·Elevation: 1'251 m ·United States

Radius · 50 km

Nearby infrastructure

Up to 3 nearest sites per category

Airports

  • Buchanan FieldUnited States · CCR · KCCR
    18.4 kmStraight-line distance
  • Oakland San Francisco Bay AirportUnited States · OAK · KOAK
    18.8 kmStraight-line distance
  • San Francisco International AirportUnited States · SFO · KSFO
    32.7 kmStraight-line distance

Source: OurAirports · Dataset date: 2026-09-26

Nuclear power plants

  • Vallecitos nuclear power plantUnited StatesPermanently shut downReactor units at site: 1
    46.0 kmStraight-line distance

Source: Global Energy Monitor · Global Nuclear Power Tracker · Dataset date: 2026-08

This selection shows geographic proximity, not a hazard zone or confirmed impacts. Distances use recorded site coordinates. Sources & data dates

California

Context for this earthquake

26 Sep 2025 – 26 Sep 2026 · M ≥ 2.0 · 2,424 Catalogue entries

Of 2,423 other entries for this area and period, 1,041 have a higher stored magnitude. Different magnitude types and reports not yet merged limit the comparison.

Open seismic profile

Historic earthquake map · United States

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Explore recent and long-term earthquake activity in this country. Use filters to narrow down by magnitude, depth, and date range.

Country statistics · United States

Country overview
View earthquake KPIs, strongest and latest events, and averages for this country.

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