Earth quack in Los Angeles is a real concern to the US economy that after so many other natural disaster someone like this could take it to ugly place. California IGNORING ‘dangerous’ earthquake zone that will unleash ‘GREAT DAMAGE' A FAULT line that could reduce major cities in California to rubble by triggering a dreaded “big one” earthquake is being ignored, a leading seismologist has warned. Last month a magnitude 4.0 earthquake struck between Lake Elsinore and Corona in western Riverside County, California, according to US Geological Survey (USGS). No fatalities or injuries were reported, but the earthquake, which struck at a depth of six miles (9.6 km), occurred on the “dangerous” Elsinore Fault Zone.