California has not experienced a major earthquake in its largest cities for over thirty years, but experts warn that the so-called “Big One” is inevitable, not a question of if, but when.
Significant risks extend beyond individual urban areas, impacting a vast population.
“Seventy percent of Californians live within thirty miles of an active fault,” California State Geologist Jeremy Lancaster stated during a recent informational webinar.
He highlighted the state’s vulnerabilities, noting the presence of seven active volcanoes, landslides, tsunamis, and a vast network of active faults.
In response to the potential for seismic disasters, Thursday’s annual ShakeOut earthquake drill serves as an essential reminder for residents on how to prepare and respond.
This year, Southern California will host its ShakeOut drill at the Los Angeles Emergency Operations Center in downtown, while the San Francisco Bay Area’s drill will take place in front of Oakland City Hall.
The key guideline for the drill is to drop, cover, and hold on at 10:16 a.m. on Thursday.
While this may seem second nature to long-term Californians accustomed to such drills, newcomers may find the process less familiar.
When experiencing shaking or receiving an early warning, the best response is to drop to the ground, take cover under a sturdy object like a table, and hold on until the shaking has ceased.
Wendy Bohon, branch chief of seismic hazards and earthquake engineering at the California Geological Survey, emphasized this protocol in a recent social media video.
Many instinctively feel compelled to run outside during an earthquake, but experts recommend against this reflex.
Being just outside a building can be one of the most hazardous places during an earthquake due to the risk from falling glass or bricks.
Brick structures, in particular, can collapse outward, making it especially dangerous to exit during an earthquake.
Lancaster pointed out that during the last two significant earthquakes — the 1989 magnitude-6.9 Loma Prieta and the 1994 magnitude-6.7 Northridge quakes — approximately fifty percent of reported injuries arose from falling debris.
To mitigate risks, experts advocate that dropping to the ground and staying still under protective structures can safeguard against falling objects.
Research from these earthquakes indicated that individuals moving around were twice as likely to sustain injuries compared to those who remained stationary.
Sara McBride, executive director of the California Seismic Safety Commission, noted during the webinar that most injuries recorded during these major events were due to movement-based activities when people were trying to act amid the shaking.
Studies from similar seismically active nations, such as New Zealand, corroborate that the “drop, cover, and hold on” method is generally the safest response in most situations.
Despite the guidance, some individuals might hesitate to follow it due to embarrassment or the instinct to check on children or loved ones first.
Such reflexive actions have led to injuries; for instance, a mother in Rancho Cucamonga tragically died after rushing to her child’s side and striking her head on the crib during the Northridge quake.
Fortunately, technology provides some avenues for receiving earlier warnings of an impending earthquake.
The MyShake app, developed by UC Berkeley in collaboration with the California Governor’s Office of Emergency Services, is available for free on both iOS and Android devices.
This app can provide crucial alerts from ShakeAlert, which is the U.S. Geological Survey’s early warning system.
For users positioned farther from an earthquake’s epicenter, the system utilizes modern telecommunications to give advance notice of incoming shaking, which travels slower than seismic waves.
Receiving these alerts can provide users vital seconds to prepare and implement safety measures such as dropping, covering, and holding on, or taking other precautions like placing down kitchen utensils.
Home safety is crucial in earthquake preparedness, and experts recommend visiting hardware stores to find proper securing methods for furniture and appliances.
Items such as bookcases should be strapped to walls, and televisions securely mounted to prevent them from tipping over during a quake.
Water heaters are also vital to anchor down to mitigate fire risks following an earthquake.
Homeowners should assess whether their residences require retrofitting, especially if they inhabit older structures, particularly those built before 1979 with short, flimsy walls known as “cripple walls.”
These walls risk detaching from the foundation during an earthquake, and retrofitting costs range from approximately $5,000 in Southern California to about $6,000 in Northern California.
To assist homeowners financially, the California Residential Mitigation Program offers grants that offset retrofit costs, with the registration period deadline recently extended to Friday.
Homeowners can apply for funding of up to $3,000; notably, landlords can now seek retrofitting grants for rental properties as well.
Apartment owners should also review if their buildings meet seismic safety standards, as many older buildings, classified as “soft-story” apartment structures, lack adequate support.
In earthquake situations, those living in low-lying coastal regions must also consider tsunami hazards, particularly following California’s recent tsunami warnings.
The California Geological Survey has developed maps indicating these hazard zones, allowing residents to mentally prepare for potential evacuations.
Being informed ahead of time can prevent unnecessary evacuations, as noted after some Northern California residents fled into lower-risk areas when they did not need to.
Awareness of the locations of seismic risk is essential in helping residents navigate appropriate responses.
California is notable for its unique geological landscape, which poses a significant risk for earthquakes due to the active forces shaping its mountains and oceanic coastline.
Though California is the second-most seismically active state in the U.S. (with Alaska ranking first), its population of approximately 40 million results in a high seismic risk overall.
A significant earthquake could incur costs in the hundreds of billions of dollars, and the last major seismic events of magnitude 7.8 or 7.9 have not occurred in modern records prior to 1906.
Areas prone to severe shaking typically lie close to California’s active fault lines, which encompass regions in both Southern California and the San Francisco Bay Area, as indicated by updated mapping from the California Geological Survey.
State officials are proactively taking steps toward earthquake preparedness as well.
The California Governor’s Office of Emergency Services has commenced construction on a new campus in Costa Mesa, aimed at supporting preparedness for Southern California disasters and emergencies, with its current headquarters residing in Mather.
Furthermore, a recent unanimous decision by the Los Angeles County Board of Supervisors mandated the seismic retrofit of specific high-rise concrete buildings within county jurisdiction, establishing a twenty-year deadline for compliance.
Nevertheless, numerous local governments remain unresponsive, with many older buildings still facing unsecured seismic vulnerabilities.
Additionally, concerns linger regarding the resilience of California’s water supply and utility systems in the aftermath of a significant earthquake.
The risk of post-earthquake fires presents another challenge, as questions arise about adequate fire response capabilities following seismic events.
Dr. Bohon underlined the importance of understanding earthquake procedures: “Anywhere in California can experience strong earthquake shaking, so it’s really important for you to know what to do.”
image source from：latimes
