Check out our tsunami facts and learn some interesting information related to these great walls of water that can cause so much destruction. Find out what causes tsunamis and read about some recent examples of tsunamis that have occurred around the globe.               The Japanese word for tsunami means harbor wave. Tsunamis are sometimes called tidal   waves but this term has fallen out of favour because tsunamis are not related to tides. Tsunamis are huge waves of water that are usually caused by earthquakes or volcanic eruptions.               As a tsunami approaches the shore, water may move back from the coast. If it is shallow enough the water may be pulled back hundreds of metres. If you are in the area, you can know that a tsunami is on the way when you see this phenomenon.               Regions in tsunami danger zones often have warning systems in place to give people as much time as possible to move to a safe place.               When tsunamis hit shallow water (often near the coast) they slow down but increase in height.               An earthquake in the Indian Ocean off Indonesia in December 2004 caused a tsunami that killed over 200,000 people in 14 countries.                In March 2011, the Tohoku earthquake off the eastern coast of Japan caused a tsunami that was a major factor in the death of over 15,000 people.               The tsunami waves created by the Tohoku earthquake reached a height of over 40 metres in some areas, wiping out coastal towns and causing a number of nuclear accidents. In the Tohoku earthquake over 15,000 people died mainly because of   _  .
the earthquake itself the tsunami caused by the earthquake the lack of warning systems the nuclear accidents caused by the tsunami