In 2004, the Indian Ocean tsunami was caused by an earthquake with the energy of 23,000 atomic bombs. After the earthquake, killer waves radiating from the epicenter slammed into the coastline of 11 countries. The final death toll was 283,000.
What is a Tsunami?
Tsunamis are giant waves caused by earthquakes or volcanic eruptions under the sea. Out in the depths of the ocean, tsunami waves do not dramatically increase in height. But as the waves travel inland, they build up to higher and higher heights as the depth of the ocean decreases. The speed of tsunami waves depends on ocean depth rather than the distance from the source of the wave. Tsunami waves may travel as fast as jet planes over deep waters, only slowing down when reaching shallow waters. While tsunamis are often referred to as tidal waves, this name is discouraged by oceanographers because tides have little to do with these giant waves.
How Long Does Tsunamis Last?
Large tsunamis may continue for days in some locations, reaching their peak often a couple of hours after arrival and gradually tapering off after that. The time between tsunami crests (the tsunami’s period) ranges from approximately five minutes to two hours.
Waves of Tsunamis
Tsunamis can travel at speeds of about 500 miles or 805 kilometers an hour, almost as fast as a jet plane.These waves can reach heights of over 100 ft.The first wave of a tsunami is usually not the strongest, successive waves get bigger and stronger.
Can a Tsunamis be Predicted?
Like the earthquakes that generate most tsunamis, scientists cannot predict when and where the next tsunami will strike. But, the Tsunami Warning Centers know which earthquakes are likely to generate tsunamis and can issue tsunami messages when they think a tsunami is possible.
About 80 Percent of Tsunamis Occur in the Ring of Fire
The Ring of Fire is a string of volcanoes and sites of seismic activity, or earthquakes, around the edges of the Pacific Ocean. Roughly 90% of all earthquakes occur along the Ring of Fire, and the ring is dotted with 75% of all active volcanoes on Earth.The states in the U.S. at greatest risk for tsunamis are Hawaii, Alaska, Washington, Oregon, and California.
Tips To Survive a Tsunamis
Learn the signs of a potential tsunami, such as an earthquake, a loud roar from the ocean, or unusual ocean behavior, such as a sudden rise or wall of water or sudden draining of water showing the ocean floor. Know and practice community evacuation plans. Some at-risk communities have maps with evacuation zones and routes. Map out your routes from home, work and play. Pick shelters 100 feet or more above sea level, or at least one mile inland.
Create a family emergency communication plan that has an out-of-state contact. Plan where to meet if you get separated.
Sign up for your community’s warning system. The Emergency Alert System (EAS) and National Oceanic and Atmospheric Administration (NOAA) Weather Radio also provide emergency alerts. Consider earthquake insurance and a flood insurance policy through the National Flood Insurance Program (NFIP). Standard homeowner’s insurance does not cover flood or earthquake damage.
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