There’s a new fault zone that’s been discovered off the coast of Southern California — and it’s raising alarms about the potential for a devastating earthquake and a tsunami that could devastate Los Angeles and San Diego.

Geological fractures have been discovered deep beneath the surface of the Pacific Ocean that could result a rupture stretching 100 kilometers, resulting in a tremendous earthquake that could hit 8.0 on the Richter scale and shift the tectonic plates upward, creating a huge tsunami that would race toward the California coast at frightening speeds, according to a SlashGear report on a study by geologist Mark Legg that was published in the Journal of Geophysical Research: Earth Surface.

Legg and other researchers were examining a large stretch of ocean that includes the Santa Cruz-Catalina Ridge and Ferrelo faults, both already known by scientists. They were using high-resolution mapping and taking new depth measurements to understand how the crust of the Earth was changing when they found multiple segments that could result in a tremendous rupture and a violent shift in the tectonic plates.

It’s not unheard of to have large earthquakes off the California coast, as 7.0-magnitude quakes have been recorded before, and these new findings don’t mean anyone should panic — just that SoCal residents should realize the risks and be prepared in the event that it happens.

Recent tsunamis have had devastating effects on coastal cities. The 2011 tsunami wreaked havoc in Japan, resulting in huge amounts of damage and loss of life, as well as a nuclear disaster. The 2004 tsunami in the Indian Ocean was one of the worst natural disasters of all time.