Sylmar earthquake
At 6:00 the morning of February 9, 1971, an earthquake measuring M6.6 rocked the northern San Fernando Valley, near Sylmar.The earthquake ruptured a segment of the San Fernando fault zone, a set of north-dipping, high-angled reverse faults along the southeastern margin of the San Gabriel Mountains.
It caused more than 10 miles of discontinuous surface ruptures with average displacements of about 3 feet both horizontally and vertically. A strong aftershock sequence followed the main shock and included four quakes in the M5 range.
The quake claimed 65 lives and caused more than half a billion dollars in damage, including the destruction of two hospitals, a freeway interchange and the Van Norman Dam. The most spectacular damage included the collapse of structures at Olive View Hospital in Sylmar and the Veterans Administration Hospital at San Fernando, where 49 people died.
Landslides were widespread and caused extensive damage throughout the San Gabriel Mountains..