The Northridge earthquake occurred on January 17, 1994, at 4:31 a.m. Pacific Standard Time. The hypocenter was about 32 km west‐northwest of Los Angeles in the San Fernando Valley at a relatively deep focal depth of 19 km. The moment magnitude for the earthquake is M w 6.7. The earthquake occurred on a south‐southwest dipping thrust ramp beneath the San Fernando Valley and, thus, reemphasized the seismic hazard of concealed faults in the greater Los Angeles region. The Northridge earthquake also indicates a continuing high rate of seismicity along the northern edge of the Los Angeles basin.