Northridge Earthquake 1994: A Hidden Thrust Fault, 1.82g and Valley Fever

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At 4:30 a.m. on Monday, January 17, 1994, eight seconds of violent shaking hit the San Fernando Valley in a magnitude 6.7 earthquake that caused between $13 billion and $50 billion in damage. It came not from the San Andreas but from a buried blind thrust fault about 11 miles down, later named the Northridge or Pico Thrust, a product of north-south crustal shortening along the Big Bend of the San Andreas. The quake pushed the Santa Susana Mountains up 40 centimeters and raised Northridge 20 centimeters. A seismometer at the Cedar Hill Nursery in Tarzana recorded a peak ground acceleration of 1.82g, a reading the USGS confirmed was not a malfunction.

The official toll was 57 dead, rising into the 70s with indirect deaths, and over 8,700 people were injured. Sixteen died in the soft-story Northridge Meadows Apartments, and nine stilt homes in Sherman Oaks slid down a hillside, killing four. The Newhall Pass interchange of Interstate 5 and State Route 14, rebuilt after 1971, collapsed again, and LAPD motorcycle officer Clarence Wayne Dean rode off its edge in the dark. Landslides released fungal spores that caused a Valley fever outbreak in Ventura County with 203 cases and three deaths, the first recorded link between an earthquake and the disease. The aftermath brought Senate Bill 1953 on hospital seismic safety, the California Earthquake Authority and mandatory water heater strapping.

• Broken water mains left hydrants dry, and 40,000 to 60,000 people still had no water service five days later.
• Eleven hospitals were evacuated with severe structural damage, and the USGS counted over 11,000 landslides.
• Michael Jackson moved his recording sessions to New York, and Star Trek: Deep Space Nine actors fled the Paramount lot in alien makeup.
• Wes Craven's New Nightmare worked real footage of the devastation into the film.
• All 58 buildings at Cal State Northridge were damaged, and the school reopened two weeks late using 335 temporary structures.