All in one day, California residents in the Berkeley area had Earthquakes on their mind. A day that started at 10:20 a.m. for the annual participation of more than 8 million people for the 2011 Great California ShakeOut to practice the technique of “Drop, cover and hold on” and to prepare people for earthquakes, turned into something a little more.
Hours after the great outcome for the Great California Shakeout came an Earthquake itself. The earthquake occurred along the Hayward Fault line at 2:31 p.m. on Thursday, October 20, 2011 with a magnitude of 4.2. It was centered across the bay from San Francisco and the quake was six miles deep beneath the University of California, Berkeley campus.
Then, another quake came about six hours later around the same Berkeley area. Occurring at 8:16 p.m. and at a magnitude of 3.9, according to U.S. Geological Survey, it struck nine miles deep. Seismologists determined that the second quake was an aftershock to the early afternoon earthquake.
USGS geophysicist Walter Mooney was quoted:
“This is a textbook example of an aftershock.”
Los Angeles Times reported:
“KRON-TV and KPIX-TV reported that the second temblor caused items to fall from shelves in some homes near the Berkeley epicenter. Some plaster fell from the ceiling of a business in Oakland, the San Francisco Chronicle reported. The quake also left some artwork askew at an Oakland library.”
Berkeley police reported there are no injuries or damage from either Earthquake.
The earthquake came almost 22 years after the Loma Prieta earthquake that struck the Bay area during the 1989 World Series. The magnitude-6.9 quake killed 63 people, injured almost 3,800 and caused up to $10 billion damage.