When the next “Big One” hits, it could carry a massive price tag, according to a California earthquake expert.

A magnitude 7.8 earthquake along the southern San Andreas Fault, rupturing from Imperial County to Los Angeles County, could result in an estimated $1 trillion in damage across Southern California.

That’s according to a state earthquake expert who calculated the costs based on previous disasters, including the recent Los Angeles wildfires. The estimate has also been adjusted for inflation.

“I wouldn’t say that a trillion dollars is an extreme, it could be very plausible if things go bad,” Ahmed Elbanna, director of the Statewide California Earthquake Center, told the San Francisco Chronicle.

Elbanna said damage from fires triggered by a major earthquake could account for $300 billion alone.

While the estimates are informal, they suggest such a quake could become the costliest disaster in U.S. history.

For comparison, Hurricane Katrina caused roughly $200 billion in damage, when adjusted for inflation, after striking New Orleans in 2005, according to the Chronicle.

“It’s going to be an event that California and Los Angeles have not experienced probably throughout their whole history,” Elbanna said.

His estimate is far higher than the state’s formal projections from 2008, which found that a magnitude 7.8 earthquake on the southern San Andreas Fault could cause $213 billion in losses.

The new estimate is significantly higher because California has far more assets at risk today, the Chronicle reported.

Elbanna said the state’s population, economy and infrastructure have expanded dramatically over the past two decades, and Californians are more reliant than ever on the electrical grid and internet systems. He also said climate change could amplify the destruction.

Geologists say the San Andreas Fault is experiencing its highest stress level in roughly 1,000 years.

The fault is expected to produce a major rupture about every 150 years.

The last Southern California “Big One” on the San Andreas Fault occurred in 1857. (Source: KTLA)

Story Date: July 29, 2026