The San Cayetano Fault is one of the two major faults in the river valley, and is located north of Santa Paula and Fillmore. In one area, the fault dips and almost meets the Oak Ridge Fault that runs along the south side of the Santa Clara River. The two faults have slowly been moving closer together for years, a situation closely studied by seismologists.The Santa Clara River Valley has been the focus of much fault activity: the most notable event in modern times was the 1994 Northridge earthquake that caused about $250 million in damage in Fillmore. A strong aftershock of the 6.7-magnitude Northridge earthquake caused little damage in Santa Paula, about nine miles away, when it hit two days after the quake.The San Cayetano Fault is capable of producing earthquakes of magnitude-6.5 or magnitude-7, according to seismologists. In recent years Fillmore has been the scene of minor earthquake swarms, multiple events that caused small temblors within a tight timeframe, but the February 24 earthquake was the first noticeable seismic activity in more than a year.