© Matthew Crawford/For The TimesA man rides his bicycle in 2004 in Crescent City, where a 1964 earthquake spawned a deadly tsunami.
If a 9.0 earthquake were to strike along California's sparsely populated North Coast, it would have a catastrophic ripple effect.
A giant tsunami created by the quake would wash away coastal towns, destroy U.S. 101 and cause $70 billion in damage over a large swath of the Pacific coast. More than 100 bridges would be lost, power lines toppled and coastal towns isolated. Residents would have as few as 15 minutes notice to flee to higher ground, and as many as 10,000 would perish.
Scientists last year published this grim scenario for a massive rupture along the Cascadia fault system, which runs 700 miles off shore from Northern California to Vancouver Island.
The Cascadia subduction zone is less known than the San Andreas fault, which scientists have long predicted will produce The Big One. But in recent years, scientists have come to believe that the Cascadia is far more dangerous than originally believed and have been giving the system more attention.
The Cascadia begins at a geologically treacherous area where three tectonic plates are pushing against each other. The intersection has produced the two largest earthquakes in California in the last decade - Sunday's 6.8 temblor off Eureka and a 7.2 quake off Crescent City in 2005. The area has produced six quakes of magnitude 7.0 or greater in the last 100 years, the California Geological Survey said.
