<P> The 1994 Northridge earthquake occurred on January 17 , at 4 : 30 : 55 a.m. PST and had its epicenter in Reseda , a neighborhood in the north - central San Fernando Valley region of Los Angeles , California . It had a duration of approximately 10 -- 20 seconds . The blind thrust earthquake had a moment magnitude ( M ) of 6.7 , which produced ground acceleration that was the highest ever instrumentally recorded in an urban area in North America , measuring 1.8g ( 16.7 m / s ) with strong ground motion felt as far away as Las Vegas , Nevada , about 220 miles ( 360 km ) from the epicenter . The peak ground velocity at the Rinaldi Receiving Station was 183 cm / s ( 4.09 mph or 6.59 km / h ) , the fastest peak ground velocity ever recorded . In addition , two 6.0 M aftershocks occurred , the first about one minute after the initial event and the second approximately 11 hours later , the strongest of several thousand aftershocks in all . The death toll was 57 , with more than 8,700 injured . In addition , property damage was estimated to be between $13 and $50 billion , making it one of the costliest natural disasters in U.S. history . </P>
<P> The 1994 Northridge earthquake occurred on January 17 , at 4 : 30 : 55 a.m. PST and had its epicenter in Reseda , a neighborhood in the north - central San Fernando Valley region of Los Angeles , California . It had a duration of approximately 10 -- 20 seconds . The blind thrust earthquake had a moment magnitude ( M ) of 6.7 , which produced ground acceleration that was the highest ever instrumentally recorded in an urban area in North America , measuring 1.8g ( 16.7 m / s ) with strong ground motion felt as far away as Las Vegas , Nevada , about 220 miles ( 360 km ) from the epicenter . The peak ground velocity at the Rinaldi Receiving Station was 183 cm / s ( 4.09 mph or 6.59 km / h ) , the fastest peak ground velocity ever recorded . In addition , two 6.0 M aftershocks occurred , the first about one minute after the initial event and the second approximately 11 hours later , the strongest of several thousand aftershocks in all . The death toll was 57 , with more than 8,700 injured . In addition , property damage was estimated to be between $13 and $50 billion , making it one of the costliest natural disasters in U.S. history . </P>
what was the magnitude of the northridge earthquake
what was the magnitude of the northridge earthquake
6.7
6.7