Tsunamis are giant waves caused by undersea earthquakes, landslides or volcanic eruptions. The severity of their effects depends on a number of factors, namely the magnitude of the earthquake, landslide or volcanic eruption, along with its distance from shore. Small and undetectable tsunamis occur almost every day with little to no effect, but larger tsunamis have devastating effects to life and land that are often irreversible. The central effect of large tsunamis is massive loss of human life. With no time to escape, tsunamis cause near instant death, usually by drowning, but also by collapsing buildings, electrocution and more. Since 1850, tsunamis have killed more than 430,000 people. The March 2011 tsunami in Japan left a total of 18,550 people killed and/or missing. The severe flooding that occurs as a result of a tsunami also damages sewer systems, water supplies and soil. Stagnant and contaminated water leads to malaria and other diseases, causing illness, infection and death to spread rapidly. Soil becomes salinized from sea water and debris, effecting long-term yields of crops. The tall and fast-moving waves also damage property and permanently alter the landscape, sometimes wiping out entire islands. They destroy everything in their path, including buildings, trees, power lines, bridges, cars, boats and more, leaving behind them a mass of solid waste and debris that is almost impossible to clean up. They also destroy animal life, insects, plants and natural resources. Hazardous materials and toxic substances are also a concern, as asbestos, oil fuel and other industrial raw materials and chemicals often leak as a result of property damage.
