https://www.nationalgeographic.com/science/2019/08/hidden-earthquake-risk-discovered-under-los-angeles/

Hidden earthquake risk found lurking beneath Los Angeles
The fault was once thought dead, but recent research suggests it’s likely still active—and poses a hazard to the metropolis above.

I remember the 1952 earthquake. It literally knocked me from my bed and woke me up. I was dreaming  that I was running and had tripped and fallen on a huge rock in the road. My mom heard the thump and came running. Later that morning, I walked outside. It had rained a few days before, and the dried mud had formed huge cracks. My family was living in Long Beach at that time, not too far from the Pacific Ocean.