"The Big One" is Coming to California

While 2020 has brought the trials of a pandemic, civil unrest, and political turmoil to those across the country, California and nine other states are additionally burdened by earthquakes. However, seismologists predict that Southern California is particularly at the mercy of a disastrous earthquake called, The Big One.

Earthquakes are powerful displays of mother nature that occur when pressure is released from continental plates shifting and colliding beneath the surface. Depending on the size, they can be dangerous and cause damage to landscapes in their wake. They are nearly unpredictable with the exception of seismologists who’ve developed a way to statistically estimate when a big earthquake will occur, using data from the past and present.

Since January, Los Angeles (L.A.) has experienced three earthquakes that were 4.0 and above on the Richter scale -- a scale used to measure the magnitude of earthquakes based on the size of their vibrations ranging from 1.0 to 8.0 and above. Earthquakes are considered to be light if they are between 4.0 and 4.9. Those that are 8.0 and above are classified as great and have the potential to collapse major bridges and buildings, but these are rare.

The epicenters (points of origin) of L.A.’s recent 4.0 and above earthquakes were in Sylmar, El Monte, and the Pacific Ocean -- all within a 60 mile radius of Santa Monica College (SMC). The earthquakes were classified as light, but even a 60 mile distance did not stop the vibrations from shaking the campus, according to the U.S. Geological Survey’s (U.S.G.S. ‘s) earthquake map.

No major damage was reported, but these earthquakes serve as reminders that a natural disaster can happen at any time -- specifically a major earthquake known as "The Big One," that is expected to be 7.8 or above.

SMC Geology Professor Dr. Lisa Collins has been studying earthquakes since her undergraduate years, and earned her Ph.D. in earth sciences from the University of Southern California (USC). She shared the latest prediction from the U.S.G.S., and emphasized that it is not a matter of if The Big One will occur but when.

“In the next 60 years, there's about a 60% probability that [L.A.] will have an earthquake that’s at least a magnitude [of] 6.7. The likelihood decreases with the larger earthquakes,” Collins said. She noted that this can affect today’s youth who decide to stay in Southern California, including those a part of the SMC community.

It also concerns her as a wife and mother, who now has her family to think of, compared to years ago when she first moved to California from Maryland, and was thrilled to learn about earthquakes firsthand. Today she stays up-to-date on the latest news about earthquakes in Southern California for her classes, her own interests, and for the safety of her family.

Collins said The Big One will be triggered by an earthquake on the San Andreas Fault, a well-known continental divide connecting two massive plates underground. The fault runs approximately 800 miles, starting near the border of Mexico and ending in the Bay Area, outside of San Francisco.

The San Andreas Fault is about 35 miles from L.A. and has not had a major earthquake since the 1800’s due to a bend in the fault preventing the plates from sliding. Collins mentioned that while straighter parts of the fault have shifted over the years, the bend just north of L.A. has been stuck in place; but, this might change when The Big One happens.

“The size of the earthquake relates to the amount of displacement or the amount of movement, that's going to happen on that fault. At this point, I think it's over 30 feet of displacement that we're expecting to see. So that's partly why we're expecting it to be, and why we call it, The Big One. It's going to release a lot of energy when it slips suddenly,” Collins said.

L.A.’s most recent earthquakes are connected to smaller faults that run right through the heart of the city, and can potentially cause more damage to L.A.’s metropolitan area than The Big One, due to their close proximity. In a scenario when a major earthquake hits the city, Collins said people may have to fend for themselves for two to three days before the city provides aid.

“Police officers and firemen, you’ll see them coming through, but if you need something they may not be able to help you, they may just be doing a quick assessment of what's going on and then leaving,” Collins said.

She also mentioned there may be looting, phone service will be down, and the Los Angeles International Airport (LAX) will be shut down for three days before any supplies are flown in.

To be prepared, she recommends assembling an earthquake kit with basic necessities. This includes cash to account for broken ATMs and no electricity, blankets and warm clothes, and one gallon of water per person a day. She also suggests making a plan so people in the same household can find each other after the earthquake. She’s created an in-depth list of supplies that she shares with her students and uses for her family. A similar list can be found on the U.S.G.S. website.

Some additional resources she mentioned are NPR’s podcast, "The Big One," the U.S.G.S. 's Twitter and Facebook accounts for updates on earthquakes in Southern California, the QuakeFeed phone application that alerts users when earthquakes are happening around the world, and SMC’s Earth sciences department that is partnering with the U.S.G.S. to build a station for students to learn about earthquake monitoring.

Professor Collins admitted that earthquakes are unsettling for her but she feels better knowing that she and her family are prepared. She continues to share her resources with as many students as possible, knowing that earthquake preparedness is the key to staying safe when The Big One hits.

Featured