earthquake.jpgTwo small earthquakes shook the northeast corner of Contra Costa County early Friday morning, the U.S. Geological Survey reports.

At 1:14 AM, an earthquake with a preliminary magnitude of 3.1 shook an area near Bethel Island east of Sand Mound Slough.

The quake had a depth of 6.8 miles and an epicenter located 6 miles east of Oakley and 16 miles west of Stockton, according to the USGS.

15 minutes later, at 1:29 AM, a an earthquake with a preliminary magnitude of 2.6 rattled roughly the same location

That quake had a depth of about one mile — compared with 6.8 miles for the larger tremor — and an epicenter located 6 miles east-southeast of Oakley and 17 miles west of Stockton, according to the USGS.

Bay City News contributed significantly to this report

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the author

Eve Batey is the editor and publisher of the San Francisco Appeal. She used to be the San Francisco Chronicle's Deputy Managing Editor for Online, and started at the Chronicle as their blogging and interactive editor. Before that, she was a co-founding writer and the lead editor of SFist. She's been in the city since 1997, presently living in the Outer Sunset with her husband, cat, and dog. You can reach Eve at eve@sfappeal.com.

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