This earthquake occurred on the Clamshell - Sawpit Canyon fault, an offshoot of the Sierra Madre fault zone in the San Gabriel Mountains. Because of its depth and moderate size, it caused no surface rupture, though it triggered rockslides that blocked some mountain roads. Roughly $40 million in property damage occurred in the San Gabriel Valley. Unreinforced masonry buildings, like those seen in the photographs below, were the hardest hit. Two deaths resulted from this earthquake -- one person was killed in Arcadia, and one person in Glendale died from a heart attack. In all, at least 100 others were injured, though the injuries were mostly minor.