Tsunami report

Tsunamis

Introduction:

Do you know what causes the deaths of about 200,000 people per year! It is a natural hazard called a tsunami! A tsunami is a series of waves, usually created in an ocean or another body of water by an earthquake, landslide, volcanic eruption, or meteorite impact. Tsunamis can also be formed when the surface under the water creates motions, that create earthquakes and all these things that are needed to create an Earthquake. Tsunamis can cause huge destruction and devastation when they hit coastlines. Tsunamis are huge and can travel very quickly, at about 700 km/hr, but they are 30 meters large once they “strike” (usually in open oceans, when the tsunami is beginning it is only 1 meter tall.) Did you know that when a tsunami is outstretched all the way it is 100 km across almost the length of 1000 American football fields! This is the disaster that I will talk about, but I won’t only talk about the usual things I will talk about interesting things, like characteristics of a tsunami, how a tsunami is measured in height strength and width, next I will explain the warnings and predictions, after that I will talk about places that are effected by tsunamis, when that is done I will talk about how tsunamis are created.

Characteristics:

A tsunami in the deep ocean has a wavelength of about 200 km (120 mi). Such a wave travels at well over 800 km per hour (500 mph), but due to the enormous wavelength the wave oscillation at any given point takes 20 or 30 minutes to complete a cycle and has amplitude of only about 1 meter (3.3 ft). This makes tsunamis difficult to detect over deep water. Ships rarely notice their passage. When the tsunami's wave peak reaches the shore, the resulting temporary rise in sea level is termed 'run up'. Run up is measured in meters above a reference sea level. A large tsunami may feature multiple waves arriving over a period of hours, with significant time between the wave crests. The first wave to reach the shore may not have the highest run up. Tsunamis can travel at speeds of up to 400-500 miles per hour. In deep waters (oceans), tsunamis are low and wide, often less than three feet high. There is a difference of 95 miles between the crest of one wave and the next. In shallower waters, tsunamis usually become more deadly. A Tsunami can reach up to heights of 100 feet or more and crash inland. An interesting fact about tsunamis, tsunamis velocity depends on the depth of water through which it travels.

Tsunamis travel approximately 475 mph in 15,000 feet of water. In 100 feet of water the velocity drops to about 40 mph.

Measuring a Tsunami:

Intensity scales

The first scales that were recently used to measure the strength of tsunami were the “Sieberg-Ambraseys” scale, this is mostly used in the Mediterranean Sea and the Imamura-Iida intensity scale, and is used in the Pacific Ocean. The latter scale was modified by “Soloviev”, who calculated the Tsunami intensity according to this formula.

In this formula the Hav is the average wave height along the nearest coast. This scale, that is known as the “Soloviev-Imamura” tsunami intensity/strength scale, this is used in the global tsunami catalogues compiled by the “NGDC” and “NOAA” and the “Novosibirsk Tsunami Laboratory” as the main parameter basically for the size of the tsunami.

Magnitude scales

The first scale that calculated a magnitude for a tsunami, rather than the intensity at a particular location was the ML scale, this was proposed by “Murty & Loomis” based on the potential energy. There were difficulties in calculating the potential energy of the tsunami that is why this scale is rarely used. This “theory” was based on this formula.

In this formula the “h” is the maximum tsunami-wave amplitude (in meters) it is measured by a tide at a distance “R” from the epicenter, “a”, “b” and “d” are constants used to make the Mt scale match as closely as possible with the moment magnitude scale.

Warnings and Predictions:

Drawbacks can serve as a brief warning. People who listen to drawback, can survive only if they immediately run for high ground or seek the upper floors of high buildings. In 2004, a 10 year old girl named Tilly Smith was on Maikhao beach (in Phuket), Thailand with her parents and sister, and having learned about tsunamis recently in school, she told her family that a tsunami might be about to happen. Her parents warned others minutes before the wave arrived, saving a lot of lives. A tsunami cannot be precisely predicted, even if the magnitude and location of an earthquake is known. Geologists, oceanographers (study ocean), and seismologists analyze almost every earthquake, and based on many factors can or cannot issue a tsunami warning. However, there are some warning signs of an uprising of a tsunami, and automatic systems can provide warnings immediately after an earthquake in time to save many lives. One of the most successful systems uses, bottom pressure sensors that are attached to buoys (floating device, in this case with a sensor attached.) The sensors constantly monitor the pressure of the overlying water column. This can be seen in this calculation.

In this calculation the “P” is the pressure in newtons per meter square. Were the “p” is the destiny of the sea water. And “g” is the acceleration due to gravity. Lastly the “h” is the height of the water (in meters.)

Common Places tsunamis hit:

There are lists of places that tsunamis hit/start often:

1. Most tsunamis, about 80 percent, happen within the Pacific Ocean’s “Ring of Fire,” a geologically active area where tectonic shifts make volcanoes and earthquakes common.

2. Australia

3. Japan

4. Indonesia

5. L.A (Los angles)

6. Peru

7. Papa New Guinea

8. Russia (Kuril Islands)

9. Philippines

10. Chile

How it forms:

A tsunami can be generated by any disturbance that displaces a large water mass from its “stabilized” position. In the case of earthquake-generated tsunamis, the water column is disturbed by the uplift or subsidence of the sea floor. Submarine landslides, which often accompany large earthquakes, as well as collapses of volcanic eruption, can also disturb the overlying water column as sediment and rock slump down slope and are redistributed across the sea floor. Similarly, a violent submarine volcanic eruption can create an impulsive force that uplifts the water column and generates a tsunami. Super marine landslides and cosmic-body impacts disturb the water from above, as momentum from falling debris is transferred to the water into which the debris falls. Generally speaking, tsunamis generated from these mechanisms. Large vertical movements of the earth's crust can occur at plate boundaries. Plates interact along these boundaries called faults.

Conclusion:

In conclusion I believe that these masses of destruction create a hazard for living, If we as humans would follow the instructions that are given to us, we can prevent thousands of deaths, and as we develop so dose our technology, this technology in the future just could save us from death (because of tsunamis.) There are already man areas that are jeopardized and in need of our help these are countries like Japan, Australia, Papa New Guinea and Chile. These are places we can predict earthquakes, people in these countries need help when these earthquakes hit because the hit hard, for example in Chile the earthquake had 9.5 mag. We need to be more aware of when earthquakes are going to hit, to save lives.

MLA Bibliography

1. "Occurrences of Tsunamis in the Pacific Ocean." 19 June 2009. Web. 24 Feb. 2011. .

2. Wikipedia. "Tsunami." Wikipedia, the Free Encyclopedia. 12 Mar. 2004. Web. 24 Feb. 2011. .

3. "How Are Tsunamis Formed?" Oracle. 7 Nov. 2003. Web. 24 Feb. 2011. .

4. "What Is a Tsunami?" Windows to the Universe. 15 May 2006. Web. 24 Feb. 2011. .