April 13--A magnitude 3.5 earthquake that rattled parts of Southern California on Sunday night occurred near the 46-mile-long Newport-Inglewood fault, responsible for a destructive quake that killed more than 100 people about 80 years ago.
Lucy Jones, a U.S. Geological Survey seismologist, wrote on Twitter that oil drilling, or fracking, was unlikely to be responsible for the quake because it occurred at a depth "way below the oil fields" under the epicenter. Instead, the scientist said the shaking appeared to be caused by movement in the Newport-Inglewood fault.
The fault has long been a concern for seismologists and government officials after it caused destruction in the deadly Long Beach quake in 1933 and forced changes in the state's seismic building regulations.
The Newport-Inglewood fault, beginning just off the Orange County coast and extending 50 miles northwest through Long Beach, Inglewood and into Beverly Hills, has been the subject of grim quake scenarios because it runs directly under some of the most densely populated areas of Southern California.
The Long Beach quake was a 6.4 temblor centered off the Orange County coast that killed 115 people mostly in Long Beach and Compton. That was the second-largest number of fatalities in a California temblor in recorded history. Damage to school buildings caused by that quake led to major steps toward earthquake-resistant construction in the state.
It was one of the first faults covered by a state's earthquake law prohibiting construction on active faults and requiring developers to perform studies identifying them.
Sunday's quake occurred at a depth of six miles at 9:17 p.m. Sunday and was about 2,000 feet from a smaller magnitude 2.5 tremor reported at 4:35 p.m., according to the USGS. The earlier quake was considered a foreshock to the larger quake Sunday night -- which was followed by a 1.3 magnitude aftershock at 10:37 p.m.
Times staff writers Rosanna Xia and Matt Hamilton contributed to this report.
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