The US Geological Survey has simulated the effects of a 9.1-magnitude earthquake off Alaska—and for southern California, the results could be disastrous. Some 750,000 would need to evacuate coastal areas within a matter of hours as floods spread in Long Beach and Orange County, the Los Angeles Times reports. The region is peppered with low-lying communities that have little built-in protection from the ocean, including Marina Del Rey and areas stretching from the ports of Los Angeles and Long Beach to Newport Beach.
The tsunami could cause damage to the tune of $8 billion; the waves would move along the coast down to San Diego and possibly move inland via rivers. Northern California would actually see larger waves, reaching as high as 23 feet. But the north has a less-developed coastline and more cliffs to protect it. "The idea (of the study) is to say: Look, these are not distant events, these could actually happen here," says a scientist. Experts say such a disaster could occur about once in several centuries. "Your life depends on how you respond," says the head of the study. (Read more tsunami stories.)