Is This the “Big One”?

Tourists are strolling down Hollywood Boulevard and snapping pictures of the various stars. Suddenly, the ground begins jerking and trembling. One minute they were standing on solid ground. The next, it feels like the earth is crumbling beneath their feet. Glass shatters to the ground, and the road begins to crack. Smoke starts to darken the sky. What is happening? It’s obvious – an earthquake. The highly populated Los Angeles metropolitan area is surrounded by a large complex network of thrust and strike-slip faults. To the northern edge lies the Sierra Madre-Cucamonga thrust fault system. To the north and east are the San Jacinto and San Andreas right-lateral strike-slip fault systems. Studies have shown that California’s earthquake zones are more complex and lethal than once thought.
Southern California lies on four major faults: San Andreas, San Jacinto, Sierra Madre, and the Cucamonga fault. The San Jacinto and San Andreas faults are right-lateral strike-slip fault systems; the two sides move in opposite, horizontal directions along the fault plane. If someone looked across the fault on one side, the opposite side of the fault would have appeared to move to the right. The Sierra Madre-Cucamonga fault system is a thrust fault; the sides push towards each other. The San Jacinto fault is composed of a “complex zone of splaying and overlapping strike-slip fault segments, steps and bends, and associated zones of contractional and extensional deformation” (Dorsey). One of its major fault interactions includes “triggering of co-seismic slip on northwest-striking right-lateral faults by slip on northeast-striking left-lateral faults” (Dorsey). The San Andreas Fault is the main fault of a complex fault network along the coastal California region. The fault contains “a system of four secondary faults adjacent to the main San Andreas” fault (Lovgren). Certain sections of the San Andreas fault remain quiet for years, but as strain builds up, and if released in great