In 1933, a magnitude 6.4 earthquake struck Long Beach, killing about 120 people and becoming the deadliest earthquake in SoCal's history.
But a new study suggests it might not have been the fault...of a fault.
Earthquakes in the early 20th century, like the one in Long Beach, might have been caused by oil drilling that destabilized the earth.
While that particular drilling process no longer happens in Southern California, study author Susan Hough, a seismologist for the U.S. Geological Survey, says the discovery could rewrite our understanding of quakes in the region.