2024 the most seismically active year since 1988 after recent earthquakes in Southern California

Seismologists said Southern California is experiencing increased earthquake activity a day after a 4.4-magnitude earthquake shook homes across Los Angeles.

By mid-August, the region has had 13 earthquakes measuring a magnitude of 4.0 or greater this year. Normally, Southern California averages between 10 and 12 tremors of that size a year. 

"We are seeing an ongoing process of earthquakes happening along this fault," geophysicist Dr. Lucy Jones said. 

Jones, a renowned researcher at the California Institute of Technology, said the recent earthquake near South Pasadena happened along the Puente Hills thrust fault system, which runs from the Puente Hills above Whittier to Pasadena and downtown Los Angeles. It has the potential to cause major damage. 

"They are considered the set of faults capable of producing probably the most damage of any earthquake in SoCal because of the location," Jones said. "Because they run under old structures and densely inhabited areas."

Jones added that earthquakes here could be five to ten times more destructive than earthquakes along the San Andreas Fault. In fact, the 1987 Whittier Narrows earthquake happened along the Puente Hills thrust fault system. The 5.9-magnitude tremor killed eight people and damaged thousands of buildings. 

However, Jones said earthquakes are more common on the San Andreas fault. Major quakes along the Puente Hills Fault tend to happen thousands of years apart.