What is the causes and effects of a major tsunami event?

Question

Can you kind of make a chart? Or something, if not, its ok!

Answer 1

A tsunami can be generated when the plate boundaries abruptly deform and vertically displace the overlying water. Such large vertical movements of the Earth’s crust can occur at plate boundaries. Subduction earthquakes are particularly effective in generating tsunami.

Tsunami are surface gravity waves that are formed as the displaced water mass moves under the influence of gravity and radiates across the ocean like ripples on a pond.


In the 1950s it was discovered by that larger tsunami than previously believed possible could be caused by landslides, explosive volcanic action, and impact events when they contact water. These phenomena rapidly displace large volumes of water, as energy from falling debris or expansion is transferred to the water into which the debris falls. Tsunami caused by these mechanisms, unlike the ocean-wide tsunami caused by some earthquakes, generally dissipate quickly and rarely affect coastlines distant from the source due to the small area of sea affected. These events can give rise to much larger local shock waves (solitons), such as the landslide at the head of Lituya Bay which produced a water wave estimated at 50 – 150 m and reached 524 m up local mountains. However, an extremely large landslide could generate a “megatsunami” that might have ocean-wide impacts.

The geological record tells us that there have been massive tsunami in Earth's past.

Japan is the nation with the most recorded tsunami in the world. The earliest recorded disaster being that of the A.D. 684 Kakuho Earthquake. The number of tsunami in Japan totals 195 over a 1,313 year period, averaging one event every 6.7 years, the highest rate of occurrence in the world. These waves have hit with such violent fury that entire towns have been destroyed.

On December 26, 2004, an undersea earthquake measuring 9.3 on the Earthquake Magnitude scale occurred 160 km (100 mi) off the western coast of Sumatra, Indonesia. It was the second largest earthquake in recorded history and generated massive tsunamis, which caused widespread devastation when they hit land, leaving an estimated 230,000 people dead in countries around the Indian Ocean.

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Bristol Channel floods resulted in the drowning of an estimated 2,000 or more people, with houses and villages swept away, farmland inundated and livestock destroyed, wrecking the local economy along the coasts of the Bristol Channel, UK. Some churches have plaques up to 8ft above sea level to show how high the waters rose.

Answer 2

Hey there, im a marine scientist and sometimes I can go on and on about this kind of stuff, but stick with me. If you get sick of me just delete me or something :)

The most common cause of tsunamis are earthquakes that occur on the ocean floor. Often these quakes occur at boundary lines where tectonic or continental plates meet. These are known as convergent plates. When the plates push against each other, pressure builds over time until a critical point is reached. The plates slip and thrust past each other lifting or dropping the seabed floor. This process is known as subduction. In the process the displaced water rushes outward in a 360-degree circular pattern forming a series of radiating waves like enormous ripples just like when you through a stone in a lake.

Though a tsunami in open ocean rarely reaches higher than a few feet it is a very deep wave packing lots of power, making it significantly different from surface disturbances, like true ripples or wind-generated waves. A tsunami crest can be a1000 kilometers long, but because the height is minimal it usually cannot be detected in open ocean, you can be on a fishing boat and it can go right by you and you won't even notice. As it moves outwards it can travel as fast as a passenger jet at (724 - 965 kph) racing towards shores hundreds or even thousands of miles away.

As it approaches shore and depth decreases the tsunami will slow but the power it contains continues to roll forward increasing amplitude or height. Waves can rise 100 feet (30 meters) but more often its arrival is much more subtle. The ocean may draw back from the shore so far that it disappears from view before it starts flowing back in, not as a wave at first but more like a bathtub quickly rising.

Within seconds the water level can rise 30, 60, even 100 feet (up to 30 meters) above sea level, becoming a rushing wall of water moving up to 64 kph (40mph) overtaking and lifting everything in its path. The force can easily crush homes or other structures, carry off vehicles, uproot trees and flood low-laying coastal areas up to 1.6 kilometers (1mile) inland.

Hope this helped a bit. Sorry its a bit long :)

Answer 3

I am not certain what kind of chart you want. However, the site below has quite a bit of information which I think you will find helpful:
http://www.seed.slb.com/en/scictr/watch/living_planet/tsunami.htm

Answer 4

Please visit the slide show of mine. I have issued the warning 2 hours before it struck our Indian coast. Meteorological department has not yet approached me to find out what was the technology I adopted to issue the warning. I used a simple earthquake alarm and my knowledge in seismology to issue the warning.
My Community in Orkut
http://www.orkut.com/Community.aspx?cmm=26068261
Presentation slides
http://asia.pg.photos.yahoo.com/ph/quake

Answer 5

Earthquake = drowning.

Answer 6

the major cause is underwater earthquakes.
the tides and sealevel are effected by them.