While a Mercalli Intensity of VIII ( Severe ) covered a large swath of territory relatively close to the epicenter (including the cities of Los Gatos, Santa Cruz, and Watsonville ) further to the north, portions of San Francisco were assessed at intensity IX ( Violent ). At more than 44 miles (70 km) distant, the San Francisco Bay Area recorded peak horizontal accelerations that were as high as g , and close to the epicenter they peaked at more than g . In a general way, the location of aftershocks of the event delineated the extent of the faulting, which (according to seismologist Bruce Bolt ) extended about 24 miles (40 km) in length. Because the rupture took place bilaterally, the duration of strong shaking was about half of what it would have been had it ruptured in one direction only. The duration of a typical shock with a comparable rupture length would have been about twice as long.