Four earthquakes centered in the San Ramon area of Contra Costa County struck beginning at 9:38 a.m. this morning.according to the United States Geological Survey .

The small swarm beginning with two back-to-back 3.7 quakes followed by a 3.0 and a 2.9, all preliminary magnitudes.

For real-time quake activity in the past 24 hours, check our NBC Bay Area Quake Tracker page .

This is a developing story. Details may change as more information becomes available. Stay tuned for updates.

BAY AREA QUAKE CENTRAL

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