Underwater landslides, huge underwater erupting volcanoes, meteorites falling into the ocean and underwater earthquakes can cause tsunamis. Tsunamis are not like other waves because they are not caused by wind. The most common type of earthquake that could cause a tsunami is the kind that moves vertically in the Pacific Ocean. Probably the most destructive tsunami was caused by the explosive eruption made by the volcano Krakatoa. That tsunami killed 36,000 people.