Loma Prieta earthquake damage. Jack-knifed lorry on a damaged road bridge with police on motorcycles patrolling the area. This is the Nimitz Freeway (Interstate 880), Oakland, San Francisco, California, USA. It was damaged during the Loma Prieta earthquake, which occured on October 17 1989, lasted 15 seconds and had a surface magnitude of 7.1. It was the worst earthquake in the San Francisco Bay area since 1906. A tsunami wave measuring around 1.2 metres in height travelled from Santa Cruz to Monterey. The earthquake killed 63 people throughout northern California and many properties were destroyed, which left more than 12,000 people homeless.