Catalina Is Sinking And Could Trigger A Tsunami, Says Study

Catalina Island could be slowly sinking into the sea and has the potential to to trigger a devastating tsunami that could hit Los Angeles.According to a new study by Stanford graduate student Chris Castillo, Santa Catalina Island is sinking at a rate of about 1 millimeter every five years—which would mean it could be completely underwater in 3 million years. That doesn't make it sound like a pressing matter, but the side of Catalina facing the mainland is apparently sinking at a faster rate, potentially triggering a tsunami-causing landslide according to the L.A. Times.

"It's still something that could do significant property damage, especially for the marinas," Castillo said. "If you see something that could be dangerous, you need to find out more about it."

Underwater images of the seafloor off Catalina show that a massive landslide that occurred about half a million years ago. Castillo fears that another one of those could happen again in the future and hit the ports of Los Angeles and Long Beach and the Orange County coasts.

Despite Castillo's findings, Rick Wilson, the California Geological Survey's tsunami program manager, says he'd be more concerned if such underwater landslides happened more recently. "We try to really focus on sources that happened either in the last 10,000 years or have the potential of occurring again in the very near future," he said.

Catalina was formed when a fault off the coast raised it off the seafloor. However, the decreased activity of the Santa Cruz-Santa Catalina Ridge is what is causing the island to sink, says Castillo. There is considerable debate, though, among scientists over whether it is actually sinking or rising. A study from 2012 found that the island was actually rising. The lead author of that study, Randall Schumann of the U.S. Geological Survey, says, "It is encouraging to see that scientists are continuing to determine a definitive answer to this complex question."