A 7-magnitude earthquake will strike the Bay Area in the next 30 years and cause five to 10 times as much damage as the Loma Prieta quake did a year ago, a leading federal geophysicist says.

"I think the likelihood of large earthquakes in your lifetime and mine . . . is so high that the question of whether the probability is 67 percent or 80 percent is a non-question," Allan Lindh of the U.S. Geological Survey in Menlo Park said Tuesday.The Bay Area was lucky that the 7.1-magnitude Loma Prieta quake occurred where it did, he said.

"It occurred in the most godforsaken, desolate set of mountains in the whole Bay Area," 50 miles from its urban core, Lindh told an audience of several hundred at an anniversary conference on the quake at the Hyatt Regency.

Lindh, who has spent his professional life examining Northern California earthquake faults, said a study of the area's seismic history indicates that it is about to enter a period of intense activity.

"We have to expect the next magnitude-7 quake" on one of the three faults, and "it will have an impact five to 10 times at least as large on this core, older urban area."

The Loma Prieta earthquake caused more than 60 deaths, directly affected more than 85,000 individuals, families and businesses. The U.S. Geological Survey estimated that it caused $6 billion in damage.