Consecutive 3.5-magnitude earthquakes near San Ramon shook large portions of the Bay Area on Monday afternoon, according to U.S. Geological Survey data, continuing the East Bay's torrent of temblors.
USGS officials reported that the pair of earthquakes struck within seconds of each other at 4:21 p.m. along the Calaveras Fault, which intersects the Hayward Fault.
These were the two largest of 13 earthquakes above 2.5-magnitude that USGS officials have reported in San Ramon or nearby within the past week.
Counting earthquakes of lower magnitude, there were 201 small shakers in the past week as of 5:20 p.m. Monday. Eleven of those earthquakes were registered by the USGS system within the preceding hour.
Besides the 3.5-magnitude duo, Monday's second-largest temblor occurred at 4:02 p.m., when a 2.8-magnitude earthquake struck the area. That earthquake centered on the border of San Ramon and Danville, in the vicinity of the Crow Canyon Country Club at 711 Silver Lake Dr.
It was the same location that a 3.4-magnitude earthquake struck at 6:10 a.m. Thursday, according to USGS data. At the time, that was the largest temblor in the recent quake swarm. People as far away as Vallejo and Sunnyvale felt it, according to a USGS reporting system.
Areas north of Vallejo and south of San Jose reported feeling the 3.5-magnitude shakers Monday, according to the USGS.
Police dispatchers from San Ramon and Danville said that they received no calls regarding injuries or structural damage.