On Monday, Oct. 14, 2019, an earthquake of a 4.5 magnitude struck the San Francisco Bay Area at around 10:33 p.m. According to the U.S. Geological Survey, the earthquake originated from Pleasant Hill, CA, with a depth of about nine miles. 

Although the quake was felt strongly throughout Contra Costa County, the U.S. Geological Survey stated that the quake was felt from San Francisco, Oakland, San Jose and Santa Rosa.  

Christiana Buyson, a third-year Sonoma State student, stated that she felt the earthquake in Rohnert Park on Monday night.  

“I was in my house during the earthquake and I was laying in bed on my phone, which is the top bunk and my roommate was sleeping on the bottom bunk. I felt the bed shake and I looked around and saw that the walls were shaking too. It was a slight shake, nothing too hard but I feel like there’s going to be a big one coming soon.” 

There was a 2.5 magnitude foreshock that took place just ten minutes before the 4.5 magnitude earthquake in Pleasant Hill, according to the U.S. Geological Survey. 

“Yesterday’s earthquake occurred in a region between large, well-known strike-slip faults in the San Francisco Bay Area. The earthquake appears to have occurred in a well-known Calaveras fault and the well-known Concord-Green Valley fault,” states seismologists on the USGS website.  

There is a 72% probability of the Bay Area experiencing a quake of a 6.7 magnitude or higher in the coming decades.  While Monday night’s earthquake was located some distance from Sonoma County, it “serves as a reminder that earthquakes do and will happen in tectonically active regions, so it is always wise to be prepared,” states USGS. 

The last earthquake to wake Sonoma State was in 2014, when a 6.0 magnitude earthquake shook Napa County and the north San Francisco Bay Area, the largest in the Bay Area since the 1989 Loma Prieta earthquake. Many people, including Sonoma State faculty, staff, and students, suffered injuries from falling debris and people attempting to run for safety. These smaller earthquakes serve as reminders that there are predictions of a more significant, damaging earthquake, according to seismologists. 

Although the quake was felt by some in Sonoma County, others didn’t even notice that the earthquake had occurred.  Tyree Hornbeck Jr., a third-year Sonoma State student, was at his home in Cotati on Monday night when the earthquake shook the Bay Area. 

“I was at home getting ready for bed and didn’t even realize it was happening, but I knew it happened because everyone was instantly snapchatting me asking if I had felt the earthquake. I heard movement but assumed it was someone coming home because I heard the door shaking, it hadn’t occurred to me that an earthquake was happening.”

No injuries have been reported from the earthquakes, but officials are investigating if the shaking caused a fire at an oil storage facility in Crockett, which occurred the following day on Tuesday, Oct. 15, 2019. 

More aftershocks are likely to occur in the  following weeks near the mainshock, and when there are more earthquakes, there’s a greater chance of a larger earthquake which could cause damage, according to the USGS. Their website advises everyone to be aware of possible aftershocks, “especially when in or around vulnerable structures such as reinforced masonry buildings.”

For more information on how to be prepared in the case of an earthquake, visit Sonoma State’s risk management and safety services “Earthquake Response” website here: https://web.sonoma.edu/risk/emergency/earthquake.html