1971 San Fernando earthquake
Template: Infobox earthquake / maintenance / time missing template: Infobox earthquake / Maintenance / tsunami missing template: Infobox earthquake / Maintenance / injured missing template: Infobox earthquake / maintenance / property missing
Sylmar
The San Fernando Earthquake of 1971 ( also known as Sylmar earthquake ) (14:00 UTC) occurred on February 9, 1971 at 6:00:55 clock time, in the San Fernando Valley near Sylmar, a suburb of Los Angeles, with a magnitude Mw of 6.6.
The earthquake is known by different names. Seismologists call it " San Fernando earthquake," as the United States Geological Survey (USGS ). " Sylmar Quake " or " Sylmar Earthquake " is the name given to the quake initially by the local news media, because the worst damage to the Olive View Medical Center in Sylmar occurred. The victims of the quake designated it as " February Ninth ', the' quake of February 9 ".
Location of the earthquake
The Southern California Earthquake Data Center located the hypocenter in 8.4 km depth, the epicenter was on the seen of Sylmar from other side of the San Gabriel Mountains in the Iron Canyon in the area of Sand Canyon, Canyon Country. Due to the location of the epicenter between Sylmar and San Fernando these settlement areas were most affected by damage, as well as the northeastern portion of the San Fernando Valley.
The earthquake was caused by a rupture on the San Fernando fault zone, a bevy of north incident, steep thrust faults on the southeastern edge of the San Gabriel Mountains. It caused a discontinuous zone of surface fractures with an average horizontal and vertical offset of one meter. A series of strong aftershocks included a four earthquakes of magnitude 5.
Damage
The earthquake claimed 65 people and caused property damage of more than $ 500 million, including the destruction of two hospitals, two motorway junctions and part of the lower dam of Van Norman Lake. The damage to the dam gave rise to the fear that he could collapse in parts or completely. Great confusion provoked by the fact that different places complete evacuation of 40,000 people ruled, others a voluntary evacuation of areas of the San Fernando Valley below the dam. The communication was complicated by the interruption of telephone and power lines. Likewise partially broke the water supply together.
Most of the victims called the collapse of the Veterans Administration Hospital in San Fernando, where 49 people died. The Olive View Hospital in Sylmar, which had only been opened a month earlier, almost half a meter was pushed off its foundations, so that the first floor collapsed and three patients and an employee under the rubble lost their lives.
Twelve overpasses collapsed, including the intersection of Interstate 5 with Interstate 210 ( Foothill Freeway), where two people were killed. Even the recently completed Newhall Pass Interchange, the intersection of Interstate 5 ( Golden State Freeway) and California State Route 14 ( Antelope Valley Freeway), was destroyed by the earthquake. The Newhall Pass Interchange has been equipped with reinforced components in the reconstruction, but broke 23 years later at the Northridge Earthquake of 1994 back together.
Widely occurred landslides, which caused severe damage in the San Gabriel Mountains.
Legislation
In response to the earthquake, the building regulations have been tightened. In 1972, the Alquist Priolo Special Studies Zone Act was passed accordingly. This prohibits the construction of buildings on active faults to reduce the risk of building damage due to fault rupture.