San Francisco residents were shaken by a 4.0 magnitude earthquake on Monday morning, according to a recent report published by Reuters. The two small quakes took place one after another, but authorities reassured people in the area that no major damages were produced during these episodes.
Based on the information provided by the U.S. Geological Survey, the first 2.9-magnitude seism was registered at 5:33 a.m. The epicenter of the earthquake was located at about eight miles northeast of San Francisco in the city of El Cerrito. Eight seconds later, another quake started, this time a little bit stronger than the first one. Geophysicist Paul Caruso told the press that the second seism had a 4.0 magnitude.
The effects of the earthquake could be felt within a 60-mile radius from Santa Rosa in the north to Santa Cruz in the south. Despite this, authorities working at the California Highway Patrol, San Francisco police and El Cerrito police stated that no immediate calls were made from people reporting injuries or damages. The only problem that San Francisco residents experienced after the quake was that the Bay Area commuter trains were delayed to inspect the tracks.
After close analyses, seismologists were able to determine that the seism was caused by the Hayward Fault, an active fault that runs across the eastern San Francisco Bay. Such episodes were long time predicted by the USGS report. In fact, in 2003, seismologists stated that there were 27 percent chances for the Bay Area to be affected by a magnitude-6.7 or higher earthquake in the following 30 years.
The recent attention that the media has paid to the Hayward Fault raised a lot of concern among people living in San Francisco, more specifically they were afraid that the 2003 USGS report could turn out true. Seismologist David Schwartz, however, declared that people have nothing to worry about these two small quakes. In his opinion, the 4.0 magnitude quakes are only meant to prove that there is ongoing activity on the fault.