According to the U.S. Geological Survey, Monday’s 4.4 magnitude earthquake near Los Angeles’ Highland Park neighborhood occurred along the Puente Hills Fault, also known as the Puente Hills Thrust Fault system.

This 25-mile-long fault runs from the Glendale/Pasadena area to Puente Hills and has been extremely active in recent months. The same fault was the site of a magnitude 3.4 quake on June 2 and a magnitude 2.8 on June 4.

"That fault runs right through Los Angeles, which is why we need to be concerned about it,” said Dr. Lucy Jones, a Caltech researcher and California’s preeminent seismologist. “It has the potential for a very large earthquake. It has been modeled up to magnitude seven and a half.”