What Caused The Northridge Earthquake

At 4:30 a.m. Pacific Standard Time on January 17, 1994 Northridge, California was hit by a magnitude 6.7 Earthquake that shook for nearly 20 seconds. The natural disaster was a blind thrust earthquake, which occurs along a thrust fault, but shows no sign on the Earth’s surface, thus the term “blind”. The Earthquake was centered in Northridge, which is approximately 20 miles west/northwest of Los Angeles. The powerful shock was felt at distances of 400 kilometers from the epicenter. It produced record-breaking ground acceleration, which left sixty people dead, 7,000 injured, 20,000 homeless, and over 40,000 buildings damaged in Los Angles and surrounding counties. The Earthquake caused the collapse of overpasses along the Santa Monica, Antelope Valley, Simi Valley, as well as the Golden State Freeway. In addition, numerous fires broke out due to gas line ruptures causing further damage to the
The main shock of the Northridge Earthquake ruptured on a hidden fault approximately 18 Kilometers beneath the surface for roughly 8 seconds. The rupture proliferated upward and northwestward alongside the fault at around 3 kilometers per second. The resulting size of the rupture was between 15 and 20 kilometers and concluded at a depth of 5 to 6 kilometers. Unfortunately, the greatest seismic energy was directed toward the most populated areas in the northern regions of the San Fernando Valley. The Earthquake caused significant damage to surrounding areas within approximately 4,000 square kilometers, forcing the land surface upward in the shape of an asymmetric dome, primarily due to uplifting of the valley and surround mountainous areas. According to USGS, the Santa Susana Mountains were moved by as much as 52 centimeters. The northern part of the valley was uplifted as much as 20 to 40