It could happen at anytime, anywhere. It starts with distant rumbling followed by the subtle sway of the ground beneath, the superficial evidence of a tumultuous tectonic tumble seething underground.
San Francisco has experienced several earthquakes during the past few months, with three at or above 3.8 magnitude during October.
“I’ve been here for three months and I’ve already felt four earthquakes,” said Megan Donnelly, a recent SF State transfer student from Vallejo, living in Parkmerced. “We’re on the tenth floor, so it was really scary.”
San Francisco lies directly in between the San Andreas and Hayward fault lines, the latter of which is responsible for the city’s historic 1906 quake of 7.8 magnitude and the most recent shakes.
“The Hayward (fault), that’s the one that’s been busy lately,” said John Caskey, associate professor of geosciences specializing in neotectonics at SF State.
Caskey, who often works closely with the U.S. Geological Survey, said that earthquakes of a magnitudes of 3 were no cause for alarm.
According to the USGS, there were 13 earthquakes in the Bay Area in the last week alone.
“Sometimes it’s good, we have small little shaking to release energy,” said Cheng Chen, an assistant professor of civil engineering specializing in earthquake engineering.
While the San Francisco building codes constantly evolve, many structures may not be retrofitted to current safety standards. In 2006 SF State drafted a campus master plan that deemed the science building, the Creative Arts building, and HSS building as “building systems in poor condition.”
Chen said the new library will be the safest building on campus once it opens, since newer buildings must be structured according to the most up-to-date safety codes.
Despite the city’s frequent earthquakes, most injuries occur from events other than falling buildings.
“People get hurt by non-structural components, for example, bookshelves falling, glass windows breaking,” Chen said. “In major earthquakes the ceiling caves in.”
Chen, who specializes in structural and earthquake engineering, recommended the old adage of finding a desk to take shelter under as a tried and proven method for preventing injury from most quakes.
According to the USGS, there is a 63 percent probability that there will be a major earthquake of 6.9 magnitude or more within the next 25 years. But Chen was quick to make sure the probability did not cause alarm.
“I don’t want to be misinterpreted,” Chen said. “Panic is not the right word, but people should just realize that earthquake preparedness is important.”
This story was updated on Jan. 19 to correct an error in fact that the last seismic upgrade to a building on campus was in 2003. The last seismic upgrades to take place on campus were the John Paul Leonard Library in 2012 and Parking Lot 20 in 2011.