Natural Disasters ProjectGlobal Geography 12

Project Done by Chris Currie and Josh Lewis

May 5, 2003

One natural disaster that rarely leaves anyone to recount the story is Tsunamis. Probably one of the most devastating and destructive natural forces on the planet. For thousands of years Tsunamis have struck innocent coastal cities and villages laying waste to countless kilometers of land, and taking away innocent lives. In geography studying the processes on Earth and to understand everything that happens, both above and below the surface is the goal, and within the pages of this report, it is hoped that some light is shed upon this fascinating and deadly natural disaster.

Introduction

Basic Background

The word Tsunami comes from Japanese language and means “harbor wave” in English. This is an accurate description because Tsunamis strike coastal villages, bays, and harbors. Basically a tsunami is a huge wave that originates in deep water. An event that alters the equilibrium of the ocean surface sends small waves outward. These waves are small at first but contain a large amount of water and when they finally reach the coast they are gigantic walls of water sweeping away anything and everything in its path. In the past people have called Tsunamis “tidal waves” this is not true for this natural disaster has nothing to do with the tide. Tides are controlled by the gravitational forces of the sun, moon, and the planets. Also Tsunamis have been called “seismic waves” this is sometimes true but not all Tsunamis are caused by underwater earthquakes but by other means which will be discussed later.

Japanese Form of Tsunami

“Ring of Fire”

The ring of fire is the region basically surrounding the Pacific Ocean and is also commonly called the pacific basin. Tsunamis generally occur within this zone as well as earthquakes volcanoes and other seismic activities. In this 32 000 km long area are oceanic plates that slip and slide underneath the continental plates the result is often felt as an earthquake or tsunami. Past Tsunamis have struck coastal cities along the ring of fire and created devastating damage, for example in 1996 Peru was hit, and in 1998 Papua New Guinea. When Tsunamis occur is beyond the capability of scientists to predict but going by Tsunamis from the past scientists can get an idea of certain “hotspots” for Tsunami activity and always be on guard with warning systems.

The Awesome Power!Tsunamis have very small beginnings, and yet when they reach shore become such forces of destruction and mayhem. A tsunami can be created in a variety of ways, but basically any event that disables the equilibrium of the ocean’s surface whether it be caused by underwater earthquakes, landslides, or volcanoes or be even caused by large meteors. When a tsunami is formed an upheaval of water is sent to the surface and in an effort to stabilize the oceanic equilibrium smaller waves begin to spread outward. Ships at sea cannot even tell these waves are out of the ordinary and it passes them unaffected. But when these waves reach the coast and begin to come upon shallow water they begin to increase in size, as the water depth grows shallower and the tsunami slows down however when this happens the waves begin to pile up on another and they carry a huge amount of water. Water from the coast is sucked into the ocean much like the tide, probably where the misleading “tidal wave” had come from, and to a unlucky person viewing this event it would seem as if a huge wall of water were rushing forward until it comes crashing downward, upon the land washing away sand, stone, soil, buildings, and people. Often times a tsunami is followed by several smaller tsunamis but the first one when it reaches shallow water can reach up to thirty feet high and can travel 725-800 km per hour.

The three basic steps of Tsunamis:

1: A disturbance disrupts the ocean floor and sends a huge mound of water upward.

2. Waves travel outward in an attempt to stabilize the ocean’s equilibrium.

3. When the waves reach shallow water they begin to slow and pile up on each other, creating a massive wall of water and striking the coast with tremendous force.

Brief Overview of how Tsunamis are Created

Prevention

With large forces traveling at such high speeds, a tsunami could travel from Peru to Japan in a matter of twenty-one hours, these natural disasters are some of the fastest moving things on the planet, so it seems a reasonable precaution to have warning systems in place. Tsunami Warning System in the Pacific is one and is in place to try and detect underwater earthquakes and notify the public before casualties are sustained, two centers of this system include one in Alaska and one in Hawaii two “hotspots” for tsunami activity. Seismic activity, though not always relevant to tsunamis, can be picked up by seismographs to help aid in the speed and origin of the tsunami.

Conclusion In an overview Tsunamis are

dangerous, geological nightmares. Along with their counterpart, earthquakes, tsunamis can lay waste to kilometer after kilometer of coastal regions. While they have humble beginnings started by a earthquake miles beneath the calm surface of the ocean, the devastating reach of this natural disaster moves quickly and packs a heavy punch. Thousands of lives have been lost because of tsunamis but we as scientists are learning, day by day, tsunami by tsunami, and soon we will have protection against this mighty force. But here is the question, now that so light has been shed on Tsunamis, are you living near the coast?

•“Understanding Plate Motions” http://pubs.usgs.gov/publications/text/fire.html (April 2003)•“Tsunami!” http://www.ess.washington.edu/tsunami/intro.html (April 2003)•“Tsunamis on the Move” http://www.nws.noaa.gov/om/brochures/tsunami3.htm (April 2003)•“What is a Seismograph” http://www.thetech.org/exhibits/online/quakes/seismo/ (May 4, 2003)•“Occultopedia, Tsunami” http://www.occultopedia.com/t/tsunami.htm (May 4, 2003)•“Tsunami” Funk and Wagnalls New Encyclopedia 1985 ed.•“Tsunami” The World Book Encyclopedia 1993 ed.•Lauber, Patricia. This Restless Earth. Random House Inc.: New York, 1970•Wyckoff, Jerome. The Story of Geology. Golden Press: New York, 1976•Birkeland, Peter W. and Larson, Edwin E. Putnam’s Geology. Oxford University Press: New York, 1982

Bibliography