Amos and Carla Blackmon have been front and center for all the action this week. Their one-story town house sits right next door to a spot in Contra Costa County where, as of Tuesday afternoon, the largest of 250 quakes over the past week was centered. That’s what they’ve been told by the earthquake experts at the U.S. Geological Survey. “It’s unbelievable that they’ve tracked it to here,” Carla Blackmon said.

The ground around them has been shaking since Oct. 13, when the growing swarm of quakes began. The quakes — ranging from the hardly perceptible magnitude 0.8 to a more robust 3.6 — have been occurring every few minutes to every few hours, rattling residents in the surrounding communities, particularly San Ramon. That is the city closest to a branch of the Calaveras Fault that also runs near the Crow Canyon Country Club neighborhood where the Blackmons live in nearby Danville. And that’s where the largest of the tremors shook the ground Monday. FULL REPORT