Approximately 98% of the $5.9 billion in property damage from the 1989 Loma Prieta earthquake was caused directly by ground shaking; enhanced ground shaking was directly responsible for approximately two-thirds, $4.1 billion, of the total property loss. These observations indicate that we must understand local controls of shaking and enhancement, not just local sources of shaking. Earthquake hazard reduction efforts in the United States would benefit from improved understanding of phenomena that enhance ground shaking. -from Author