Landslides and mudflows triggered by earthquakes accounted for most of the fatalities and serious injuries in several recent earthquakes, including those in Tajikstan (1989), the Philippines (1990), and Colombia (1994) (52). Earlier this century, landslides were clearly the dominant feature in earthquakes in China that killed 100,000 in 1920 and one that killed more than 66,000 in Peru in 1970 (53). Landslides can bury villages and hillside houses and sweep vehicles off roads into ravines, especially in mountainous areas. Debris flows caused by earthquakes may also dam rivers. Such blocking of rivers may cause land upstream to flood and, if the dam is suddenly breached, may cause waves of water to be sent suddenly downstream. Both of these occurrences may pose additional hazards to human settlements.