On July 29, the greater Orange County area experienced its largest quake in years when a magnitude-5.4 event rumbled beneath the Chino Hills area. And on Oct. 2, a magnitude 4.1 quake hit the San Bernardino area. Although the shaking was felt all the way to Nevada, some paused for a moment, then went on as if nothing happened.
Living in Southern California, most take a little “shake, rattle and roll” for granted. We live in earthquake country.
However, everyone would experience the effects of a 7.8 quake on the San Andreas Fault-500,000 times bigger than the Oct. 2 event. Take a moment and ask yourself, “Will I be prepared?”
On Thursday, Nov. 13, at 10 a.m. this scenario will be used for The Great Southern California ShakeOut, the largest earthquake drill in U.S. history, giving residents the opportunity to honestly think about preparation for something that promises disaster and will permanently change the lives of all who live here.
The ShakeOut envisions what would occur during and after a magnitude 7.8 earthquake along a 200-mile section of the San Andreas Fault beginning at the Salton Sea, and effecting those all over the southern area of California. The drill will gather together not just emergency personnel but schools, hospitals, utility companies, businesses and individuals as well.
A collaboration of nonprofit, business, government and education partners together organized the drill including the United States Geological Survey, California Office of Emergency Services, and other similar agencies.
According to the U.S. Geological Survey, “Geologists selected the details of this hypothetical earthquake by considering the amount of stored strain on that part of the fault with the greatest risk of imminent rupture. From this, seismologists and computer scientists modeled the ground shaking that would occur in this earthquake.”
Others were enlisted to further create a realistic scenario including civil engineers, social scientists, economists, among others.
Using the same scenario, Dr. Jim Repka, a geologist and instructor at Saddleback College shares a hypothetical example of what those in the Saddleback College area may experience. He first says that the damage to the north of the Mission Viejo area would be more severe, especially towards Los Angeles.
“Based on the [magnitude 7.6] Landers quake in 1992, whose epicenter was also about 60 miles away, I predict the shaking would be severe,” Repka said. He said that area physical damage here may not be quite as severe because the waves had to cross a mountain range as well as transect other faults before reaching the area of Saddleback College.
He also said that most of the homes, schools, and government buildings in the vicinity were built to more modern code standards, structured and designed to withstand a major earthquake.
However, the other types of damage would be devastating. These include a loss of utility services, namely water, electricity and phone services. And, the possibility of freeway overpass collapse or bridge collapse could make accessibility for emergency services impossible.
“At a minimum, the area would be without water and electricity for at least several days,” Repka said. “Communication would be at a standstill due to overloaded circuits or downed cell towers.”
The geological composition of the area is based on sandstone and shale, a marginally harder rock than northern parts of the county which are sedimentary. “The damage caused from liquefaction would have a great impact up there,” Repka said.
An estimated 4 million people are registered to take part in the largest-ever earthquake drill in the United States.
“A lot of people are signed up in San Bernardino County,” said Lucy Jones, chief scientist for the project and a seismologist with the U.S. Geological Survey. “In Riverside County, one-quarter of their people are signed up.”
Harry Parmer, chief of police at Saddleback, is heading a committee to involve the Saddleback community in The ShakeOut. At this time, no definitive plans have been put into place, but watch campus and media outlets for further details.
“The earthquake, its damages, and resulting losses are one realistic outcome, deliberately not a worst-case scenario, rather one worth preparing for and mitigating against,” said the USGS.
The main objective of the drill is to create awareness about disaster preparation. Repka noted that an event of the magnitude of the ShakeOut would require a lengthy period of self sufficiency.
For further information, visit www.shakeout.org.