1991 Sierra Madre Earthquake
The 1991 Sierra Madre Earthquake caused rockslides that blocked several mountain roads as well as damaging many unreinforced masonary structures. In all it cost $40 million in damage. The deaths from the quake was one person in Arcadia and another in Glendale who suffered a heart attack.
The quake was unique in that there were few aftershocks and were hardly big enough to cause any noticeable shaking or damage. Also, due to the depth of the quake it never produced any surface rupture.