Dozens of Earthquakes Have Rattled San Ramon, California
Nytimes reports that San Ramon, Calif., has been rattled by dozens of small earthquakes since late last year, with the most active day bringing a magnitude 4.2 that was felt as far away as San Francisco.
Seismologists describe the sequence as an earthquake swarm that began on Nov. 9, noting about 150 quakes of magnitude 2.0 or above and 19 of magnitude 3.0 or higher; most have been quick and too weak to cause real damage.
Scientists say the activity appears to be driven by fluids moving from deep in the Earth into fractured crust, a mechanism different from large fault ruptures, and they consider it unlikely to be building toward a major, destructive quake, though they cannot predict when the shaking will stop.
The persistent shaking has left many residents on edge; some have stepped up preparedness measures, and local officials say San Ramon has emergency plans and training in place.
United States, San Ramon, California