For decades, researchers have debated whether Santa Catalina is sinking or rising. Now there is new study that makes the case that the island is sinking, albeit very slowly. A Stanford University researcher says new underwater imaging suggests Catalina could be completely submerged in 3 million years, though that remains in dispute. He also contends the movement could pose a tsunami risk for Los Angeles and Orange counties. The study’s author, Stanford graduate student Chris Castillo, said the potential threat should be investigated further. He said his conclusions came from underwater images of Catalina made by Stanford University last year.

The imaging showed evidence of ancient beaches that Castillo said have sunk below the ocean’s waves. The images also showed a large underwater landslide that occurred off the island’s northeastern shore about 500,000 years ago. If a submarine landslide happened again, with tons of rocks and dirt plunging toward the ocean floor, that could create a tsunami heading toward the ports of Los Angeles and Long Beach and the Orange County coast, he said. In fact, Castillo said his imaging suggests that the side of Catalina closer to the mainland is sinking faster, so the island is tilting at a slight angle toward Long Beach and Orange County. That would make it more likely a landslide could happen again, Castillo said. Further research is needed to better understand how big the tsunami would be, Castillo said. “It’s still something that could do significant property damage, especially for the marinas…. If you see something that could be dangerous, you need to find out more about it.” MORE