Geologists warn that tension from clashing tectonic plates in Alaska could produce underwater earthquakes and send tsunamis slamming into Hawaii and the California coast, NPR reported Thursday. The tsunamis, which can move hundreds of miles per hour and are caused by landslides and underwater earthquakes, would originate from the seafloor along the Aleutian Island. The angle of a particular trench in that area, dubbed the Semidi, poses an especially great risk to California.

A tsunami stemming from that segment would make a “direct hit” on the coastline and could be the most damaging to strike in more than a century, NPR reported.  According to geophysicist John Miller, California could endure tsunamis tantamount to the one that obliterated parts of Japan in 2011. Miller, whose team conducted research on the Semidi, worries that the segment has been “too quiet” in recent years. He fears the lack of activity is indicative of a calm before a treacherous storm. “The stress isn’t being relieved by small seismic events,” Miller said in an interview with NPR. “It suggests that it’s building up a tremendous amount of tension.” FULL REPORT