The Northridge earthquake had a magnitude of 6.7. It caused very strong ground shaking lasting up to about 8 to 10 seconds, with intense horizontal and vertical ground motion. It was the strongest earthquake to hit the Los Angeles area since the 1971 San Fernando earthquake and one of the costliest in U.S. history.
Detailed Strength and Impact
- The earthquake reached a peak ground acceleration over 1.7 g (1g equals the force of gravity), with recorded horizontal accelerations of 1.25g and vertical accelerations of 1.2g, indicating extremely strong shaking.
- The shaking impacted an area about 30 miles in diameter around Northridge, California, affecting southern Ventura and northern Los Angeles counties, with the effects felt as far as Las Vegas and San Diego.
- The event caused severe damage including collapsed freeways and buildings, extensive landslides, and liquefaction of soil far from the epicenter.
- The earthquake lasted roughly 8-10 seconds and was caused by movement on a previously unknown thrust fault beneath the San Fernando Valley.
The magnitude 6.7 quake was a major seismic event with devastating local effects due to intense shaking, widespread damage to infrastructure and buildings, and significant human impact.
