Small tremor of magnitude 2.8 just reported 3 miles southeast of San Ramon, California, United States

An earthquake of magnitude 2.8 occurred early evening on Saturday, December 20th, 2025, at 6:36 pm local time near San Ramon, Contra Costa County, California, USA, as reported by the United States Geological Survey.
According to preliminary data, the quake was located at a very shallow depth of 5.9 miles. Shallow earthquakes are felt more strongly than deeper ones as they are closer to the surface. The exact magnitude, epicenter, and depth of the quake might be revised within the next few hours or minutes as seismologists review data and refine their calculations, or as other agencies issue their report.
Our monitoring service identified a second report from The Incorporated Research Institutions for Seismology (IRIS) which listed the quake at magnitude 2.8 as well. A third agency, the European-Mediterranean Seismological Centre (EMSC), reported the same quake at magnitude 2.8.
Towns or cities near the epicenter where the quake might have been felt as very weak shaking include San Ramon (pop. 76,100) located 3 miles from the epicenter, Dublin (pop. 57,700) 3 miles away, Danville (pop. 44,400) 6 miles away, Pleasanton (pop. 79,500) 7 miles away, Castro Valley (pop. 61,400) 9 miles away, Hayward (pop. 158,300) 9 miles away, and Livermore (pop. 88,100) 11 miles away. In San Francisco (pop. 827,500, 26 miles away), and San Jose (pop. 997,400, 29 miles away), the quake was probably not felt.

Earthquake data:
Date & time: Dec 20, 2025 06:36 pm (GMT -8) local time (21 Dec 2025 02:36 GMT)
Magnitude: 2.8
Depth: 9.44 km
Epicenter latitude / longitude: 37.75°N / 121.94°W (Contra Costa County, California, United States)
Primary data source: USGS
https://www.volcanodiscovery.com/earthquake/news/290004/Small-tremor-of-magnitude-28-just-reported-3-miles-southeast-of-San-Ramon-California-United-States.html