30 Earthquake Hazards in Applied Geology

Friday, 4 April 2025
8:00 AM - 12:00 PM
Granada/Hermosa

THE 1994 M6.7 NORTHRIDGE EARTHQUAKE *** A LOOK BACK AFTER 31 YEARS ***

Paper number: 30-2
Program: Theme Sessions
Time: 8:30 AM – 8:50 AM

Authors

Abstract

Residents of the San Fernando Valley and the greater Los Angeles Basin were violently jolted awake in the early morning hours of January 17, 1994, by the M6.7 Northridge Earthquake. The quake occurred on a previously unknown, blind thrust fault underlying the San Fernando Valley that intensely shook the ground for about 10-20 seconds causing catastrophic damage throughout the region. Over 9,000 people were injured and at least 72 people died due to fatal injuries and heart attacks. Property damage was estimated at over $20 billion and economic losses surpassed $40 billion making it the costliest earthquake to occur in the US since the 1906 San Francisco Earthquake and the first one to occur in an urban area since the 1933 Long Beach Earthquake. Remarkably, G-forces over 1 G (H&V) were measured in numerous locations around the epicenter; a first for modern U.S. seismic instrumentation. Additionally, due to this disaster, the State created the California Earthquake Authority, a publicly managed, but privately funded organization offering basic residential earthquake insurance.

At the time of the earthquake, my wife and I lived in Simi Valley, CA (eastern Ventura County) about 10 miles northwest of the epicenter. Our brand new 2-story tract home (3 months old) experienced strong ground shaking and suffered some damage; it literally felt like a bomb went off under our house. The brittle construction materials (interior drywall and exterior stucco, cinder blocks, and roof tiles) suffered moderate to significant damage, most notably on the first floor. The City of Simi Valley Building Inspectors yellow-tagged our house deeming it unsafe for human occupancy. We were forced to move out in one day while it underwent repairs which took over 9 months to complete. Luckily, the wooden frame of the house flexed as designed and did not incur any significant damage and most of the repairs were to the brittle construction materials.

This talk will take you on a photographic tour through the Los Angeles Basin and surrounding areas after the Northridge Earthquake using dramatic published photography from The Atlantic Magazine, Getty Images, the CSUN Geography Department, and some from my personal collection.

Geological Society of America Abstracts with Programs. Vol. 57, No. 4

doi: 10.1130/abs/2025CD-410406

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