Study Says Quake on Coastal Fault Could Top ‘Big One’

A major earthquake on a coastal fault zone through metropolitan Los Angeles would create a disaster worse than “the Big One” on the San Andreas Fault farther inland, a new state report says.

A quake on the Newport-Inglewood Fault Zone of magnitude 7 “poses one of the greatest hazards to life and property in the nation,” California’s Division of Mines and Geology said in the disaster scenario report issued Tuesday.

The fault stretches 45 miles from near Beverly Hills south through Long Beach to Laguna Beach.

The quake “would cause markedly greater damage in metropolitan Los Angeles and Orange counties than would a magnitude 8.3 (quake) along the more distant San Andreas Fault,” said Joseph Ziony, an assistant director of the division’s parent agency, the Department of Conservation.

The fault zone caused the 6.3-magnitude Long Beach earthquake in 1933 that killed 115 people and injured hundreds more.

“There is no evidence this earthquake will occur in the near future,” Ziony said. “We’re providing this scenario as a ‘worst case’ for the L.A. Basin so that officials can develop the best possible emergency-response plans.”

The report predicts that one-third of the 43,000 hospital beds in the two counties would be unusable. It does not estimate casualties, but cites a 1981 federal study indicating that a magnitude-7.5 quake could kill as many as 21,000 people, hospitalize up to 84,000 and injure 630,000 others less severely.

Shaking capable of damaging ordinary buildings and partly collapsing brick structures would occur on loose sedimentary soil throughout the basin, as far north as San Fernando and south to San Juan Capistrano, the report said.