Los Angeles metropolitan area saw shaking in line with Mercalli Intensity values of VI (Strong) or VII (Very strong), Whittier experienced effects consistent with MMI values of VIII (Severe). The old commercial district saw the worst damage, as these were the oldest buildings, and were also heavily damaged in the 1929 Whittier earthquake, a shock may have been a result of movement on the Norwalk Fault. Damage The 7:42 a.m. shock was the strongest in the Los Angeles area since the 1971 San Fernando earthquake and was felt as far as San Diego and San Luis Obispo, California and Las Vegas, Nevada. Communication systems and local media were temporarily impaired and power was cut, leaving numerous early morning workers stranded in disabled elevators. Other minor disruptions included a number of water and gas main breaks, shattered windows and some ceiling collapses. Like the San Fernando earthquake, transportation systems were again affected, but this time it was only the Santa Ana Freeway and San Gabriel River Freeways that were closed near Santa Fe Springs after pieces of concrete were dislodged and cracks were observed in the roadway. Los Angeles County+USC Medical Center took many of the injured, whose injuries were summarized by an emergency room spokesman as very bad to minor, and three people died as a direct result. While total casualties amounted to eight, the destruction of homes was significant. Throughout Los Angeles, Orange, and Ventura counties, 123 homes and 1,347 apartments were destroyed, and an additional 513 homes and 2,040 apartments were damaged. An inspection of a highway bridge on Interstate 605 revealed that there were fractures on the support columns, which resulted in temporary closure, and minor damage affected 28 other bridges. Other typical failures included more than 1,000 gas leaks, with many resulting in fire, ceramic elements on high-voltage substation equipment breaking and phone systems becoming overwhelmed. Strong motion Caltech scientists recorded the events on a cluster of twelve strong motion sensors that were placed throughout the region with a total of 87 channels of recorded data. Nine of these instruments were located on the Caltech campus, two were at the nine story Jet Propulsion Laboratory building 180 (ten miles northwest of the campus) and the final device was placed on a hillside 5 km to the west. Investigation of the accelerograms from these units revealed the strongest shaking lasted 4–5 seconds. The vertical accelerations were considered