Tsunamis

Geohazard Flyer

What happens?

Tsunamis are a series of enormous waves created by an underwater disturbance. This could be an earthquake, landslide, volcanic eruption, or meteorite, but the most common cause is an underwater earthquake. A tsunami can move hundreds of miles per hour in the open ocean and smash into land with waves as high as 100 feet or more. Once the underwater disturbance happens, waves go out in all directions and build in height.

A concern....

Tsunamis can be incredibly dangerous and wreak havoc on the coastline of a body of land. The flooding, power outages, and the like can effectively kill hundreds of people if preparation is not enacted upon. They strike the shores with a devastating force. In some cases, tsunamis have triggered other disasters such as a nuclear energy leak.

Vulnerable areas

Tsunamis can happen within any large body of water, but there are some areas of the globe where they happen more frequently. Areas with a lot of tectonic plate movement, such as the Pacific Ocean and its surrounding seas, are the most affected. (Think "ring of fire".)

Measurement

The runup is he maximum height a tsunami reaches on shore, aka the vertical distance between the maximum height reached by the water on shore and the mean sea level surface. Any tsunami runup over a meter is dangerous. At the point of impact, the runup will depend on how the energy is focused, the wave's travel path, the coastal configuration, and the offshore topography.

Examples

1) North Pacific Coast, Japan - 11 March 2011

This tsunami began as an 9.0 magnitude earthquake. It travelled at 800 km per hour and had 10-m high waves. It set off a nuclear emergency and killed over 18,000 people and costs approximately $235 billion in damages.

2) Sumatra, Indonesia - 26 December 2004

It began as a 9.1 magnitude earthquake and reached 50 m of height on impact. Approximately 230,000 people were killed and the damages sustained from the disaster are worth an estimated US $10 billion.


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Prevention

1) Simply keeping a watch on underwater seismic and oceanic activity will help let areas know when one is coming. This way, evacuations can take place as needed. Which brings up the second point....

2) Evacuate. Sometimes when the tsunami is large enough, the best way to avoid physical damage to humans is to take shelter on higher ground (or ground that is far enough inland to not be hurt by the waves or by flooding).

3) Keep listening to the radio or a news source, which will broadcast changes and developments as they happen so you can keep informed about the current situation.

4) If your home is near the coast, make sure it is elevated by at least ten feet to try and withstand the flooding.

Citations

Wikipedia. Web. 30 Jan. 2016. <https://en.wikipedia.org/wiki/2004_Indian_Ocean_earthquake_and_tsunami>.

Phillips, Campbell. "The 10 most destructive tsunamis in history." Australian Geographic. N.p., 16 Mar. 2011. Web. 30 Jan. 2016. <http://www.australiangeographic.com.au/topics/science-environment/2011/03/the-10-most-destructive-tsunamis-in-history/>.

"General Info." International Tsunami Information Center. N.p., n.d. Web. 30 Jan. 2016. <http://itic.ioc-unesco.org/index.php?option=com_content&view=category&layout=blog&id=1139&Itemid=1139>.