Volcanoes
| Volcano (i.e., Krakatoa, 1883): Less often than earthquakes,violent tsunamigenic volcanic eruptions disturb underwater crust, displacing water. Phreatomagmatic explosion (resulting from water and molten rock mixing) and implosion of the volcano's crown engulfs the magma chambers and can cause underwater eruptions, craters, or fields of magmatic hills underwater. A volcanic eruption directly causes a tsunami if the explosion of the volcano displaces the water. Volcanic activity more often relates to tsunamis indirectly, causing landslides or relating to tectonic activity. The Pacific Ocean, called the "Ring of Fire" because of the number of active volcanoes, illustrates the connection between tsunamis and volcanic activity. Not only may tsunamis and volcanoes be triggered as a result of seismic activity in the Pacific, but some volcanoes themselves have caused tsunamis and tectonic shifts. The 1883 Krakatoa, Indonesia explosion and collapse of a volcano dramatically illustrated the properties of a tsunami directly caused by volcanic eruption. This explosion created worldwide seismic waves, long-distance sonic waves, crustal plate shifts, and tsunami waves higher than 100 feet, which washed away coastal towns and villages along the Sunda Strait in both the islands of Java and Sumatra, running up more than 100 feet above sea level and killing more than 35,000 people. |