A series of small earthquakes rattled the Bay Area on Sunday morning. According to preliminary data from the U.S. Geological Society, four quakes shook the East Bay between 9:30 a.m. and 9:50 a.m. The strongest, a magnitude 3.7 earthquake, hit around 9:40 a.m. Other quakes registered a preliminary magnitudes of 3.0 and 2.9.

No one knows when the next major earthquake will strike. In the meantime, researchers are working to understand how these events could disrupt access to health care in densely populated regions—and how best to prepare for them.

The Sacramento Bee reported that at least 20 earthquakes, ranging from Mill Valley to Half Moon Bay were reported Sunday morning. The U.S. The Geological Survey said a total of eight earthquakes of at least 2.5 were recorded by noon yesterday. Seven were recorded within the city limits of San Ramon.

A series of small earthquakes struck the East Bay Sunday morning near the Alameda and Contra Costa county lines.

Dozens of small earthquakes rattled the East Bay on Sunday morning, with residents of Emeryville, Dublin and San Ramon reporting jolts.