California Earthquake Authority (CEA): Earthquake scenario reveals extensive damage to Bay Area homes is likely from Hayward-fault rupture

(SACRAMENTO) A new earthquake scenario developed by the U.S. Geological Survey (USGS), with contributions from partners, including the California Earthquake Authority (CEA), reveals that more than a million San Francisco Bay Area residents would face extensive damage to their homes after a major earthquake on the Hayward Fault.

These and other findings of the HayWired earthquake scenario were released today and will be discussed later this afternoon during a press conference at the University of California, Berkeley. HayWired describes likely impacts from a rupture of the Hayward Fault in the Bay Area. In a series of reports, the HayWired scenario team examines a hypothetical magnitude 7.0 earthquake epicentered in Oakland that strikes on April 18, 2018, at 4:18 p.m., and ruptures the Hayward fault along a 52-mile length. The title “HayWired” also reflects the scenario’s impacts on technology and communications systems.

As part of the HayWired Coalition, dozens of organizations assisted the scenario-development team in identifying community vulnerabilities. CEA supplied information on residential earthquake insurance in California and the progress of its residential mitigation programs, and will be referring to scenario findings in its ongoing educational efforts.

An analysis for the HayWired scenario from CoreLogic, a commercial provider of catastrophe-loss modeling and risk-management solutions, estimates that more than a million homes would be damaged by shaking if the projected HayWired earthquake were to occur. But because take-up of residential earthquake insurance in the Bay Area is so low, less than 10 percent of total residential losses from earthquake shaking would be insured.

“The HayWired scenario is just that—a scenario—but it’s also realistic: It could happen today,” said CEA CEO Glenn Pomeroy. “This scenario really underscores the need to prepare, so you can recover physically and financially after the ground stops shaking.”

The CoreLogic model estimates that insured residential losses from HayWired-scenario shaking could be as high as $5 billion or $6 billion. CEA has more than $15 billion in claim-paying capacity, an amount that is growing by about $2 billion per year.

Houses built before 1979 (when California adopted improved building codes) are particularly vulnerable to a Hayward-fault rupture like the HayWired scenario. Older houses can slide off their foundations during an earthquake, and the Bay Area has many such older houses: The median year of residential construction in Oakland is 1951, the median in San Francisco is 1942, and the median in San Jose is 1974.

Certain types of older houses would benefit from brace-and-bolt seismic retrofitting, which means bracing the walls between the foundation and the house’s first floor and bolting the house frame to the foundation. The Earthquake Brace + Bolt (EBB) program, primarily CEA-funded and developed by CEA and the California Governor’s Office of Emergency Services, helps homeowners lessen the potential for earthquake damage. EBB offers qualifying homeowners grants of up to $3,000 toward a code-compliant seismic retrofit. From 2014 to 2017, EBB awarded retrofit grants to more than 1,600 homeowners in the Bay Area, and in 2018, EBB registration to fund additional retrofits was open in 72 ZIP Codes within the nine-county Bay Area region.

“We’re proud of the work we’ve done to help Bay Area homeowners strengthen their houses,” said Janiele Maffei, CEA’s chief mitigation officer and the executive director of EBB. “But we know we’re just getting started—there are many more houses that still need seismic retrofitting. The consequences of not retrofitting, or of having an incomplete or improper retrofit, could be both costly and devastating.”

As Dr. Laurie Johnson, CEA strategic risk advisor and a lead author of the HayWired scenario, said, “To avoid the cascading, long-term recovery challenges that catastrophic damage to houses would bring after a major Bay Area earthquake, we must accelerate either retrofitting or replacing the region’s extensive stock of seismically vulnerable housing, and encourage greater take-up of residential earthquake insurance.”

For more information about CEA and how to reduce your risk of financial loss through earthquake insurance and mitigation, visit EarthquakeAuthority.com. And for additional information about the HayWired scenario, visit OutsmartDisaster.com.