Washington and Lee University
Friday's earthquake and tsunami in Japan brought back memories of the 2004 Indian Ocean tsunami, which killed more than 230,000 people in 14 countries. The 2004 disaster brought new awareness of tsunamis internationally and played a role in developing the warning system that went into effect almost immediately on March 11 in Hawaii and on the West Coast of the U.S., according to Romain Meyer, visiting assistant professor of geology at Washington and Lee University.
"We certainly knew about tsunamis before the Indian Ocean tsunami. But the international community was never so aware of them until after it hit," said Meyer. "In the 1940s and 1950s, we had tsunamis hitting Hawaii and Alaska. But while a small community of scientists knew what a tsunami was prior to the 2004 event, even high school students know what it is now."
As was the case in the Indian Ocean, the tsunami in Japan was the result of an earthquake in the ocean off the coast. But that is not the only way a tsunami can be triggered.
"Most of the time nowadays, people relate tsunamis only to earthquakes. A seaward earthquake that is larger than 7.5 in magnitude is able to produce a tsunami," Meyer said. "Other possibilities are major landslides, which can also trigger tsunamis. That is a fear on the East Coast of the United States. If there were major landslides on the African coast or the Canary Islands, that would cause a tsunami on the East Coast.
"The most destructive tsunamis would happen after the impact of a meteorite falling to the ocean. This would cause a huge tsunami and would be a very destructive flood. Tsunamis are byproducts of other disasters, but are very dangerous."
Meyer, who teaches a course in natural disasters, notes that part of the destructiveness of many tsunamis involves where they are apt to strike, since they often impact areas that are popular vacation spots.
"People like to vacation on the coast where it is warm and in places that look a little the tropics. So many places all around the Pacific are dangerous. So are vacation spots on the Mediterranean Ocean coast because of earthquakes in Turkey or Iran," he said. "The danger is that if the tsunami hits one of these vacation spots, the warning system is difficult.
"One effect that we saw in the Indiana Ocean tsunami was that the easiest way to restart the economy in these locations is through tourism. So you know that a region might be dangerous for people, but you restart the tourism there because it is the easiest way to get foreign currency into the country. The disadvantage is that if you go into your resort, you probably want to have some nice cabins. You don't want to have concrete major construction that might help you during a tsunami. That's not what we want to see."