The earth's surface is covered by the continents and sea floor which are parts of the world-wide system of plates that are in the very slow motion. An earthquake occurs where the edges of plates run into one another, which are called faults or fault lines. The forces along faults sometimes can build-up over long periods of time. Therefore, when rocks finally break, the earthquake happens. For example, some features generated by the forces released along the edges of plates faults are the Andes Mountains in South America, which occurred on land and the Aleutian Trench near Alaska, which occurred under water.
When rapid and powerful faulting occurs near the ocean or underneath the ocean, the large earthquake will be generated and possibly being the tsunami (What causes tsunami? , n. d. ). The process of a happening of tsunami is complicated. The magnitude and depth of earthquake, the water depth in the region of tsunami generation, the amount of vertical motion of the sea floor, the rapidity of such motion, whether there is coincident subsidence of sediments and the efficiency which the energy is transferred from crust of the earth to water in the ocean are all parts of the generation mechanism of Tsunamis.
The energy accumulates in the major plate until it exceeds the frictional forces between the two stuck plates. When this situation happens, the major plate snap back into an unrestrained position. This motion is suddenly the cause of the tsunami because it gives a gigantic push to the overlying water. Additionally, at the same time of the happening, the inland areas of the major plate are suddenly lowered (What causes Tsunamis? , 2012). However, not all earthquakes generate tsunamis. To generate tsunamis, earthquakes must occur underneath or near the ocean, be large and create movements in the sea floor.
All oceanic regions of the world can experience tsunamis, but in the Pacific Ocean there is a much more frequent occurrence of large, destructive tsunamis because of the many large earthquakes along the margins of the Pacific Ocean. Secondly, underwater landslides, coastal landslides falling into the ocean can displace enough water to generate a tsunami. Undersea landslides occur when there is a large amount of sediment dislodged from the seafloor which displaces a water column and potentially creating tsunami. Land sliding into the sea is usually caused by an earthquake.
It may also cause destructive local tsunami (What causes tsunami? , n. d. ). For instance, there is a case in 1958 where Lituya Bay in Alaska faced a tsunami caused by rockslide which an enormous boulder was loosed by an earthquake and then fell into the bay. The mass of rock striking the bay's surface created a gigantic splash, which sent water wave to the height of 1720 feet (Lituya Bay Close Up, n. d. ). Last but not least, though less common, volcanic eruptions and submarine explosions which occur near or under the ocean can all cause sufficient displacement of water to generate a tsunami.
These can be occurred in several ways. One possibility is destructive collapses of coastal. Inland and underwater volcanoes result in massive landslides. They break down and collapse, so they release large amounts of ash and debris into the water. In addition, pyroclastic flows, which are the mixtures of dense including hot blocks, ash, pumice, and gas, plunging down volcanic slopes into the water pushing water outwards. A volcano collapsing after an eruption also causes overlying water to drop suddenly. Tsunamis can also be induced by submarine volcanoes.
These underwater volcanoes can collapse downwards or spew forth lava heating the surrounding water quickly (What causes Tsunamis? , 2012). References Lituya Bay Close Up (n. d. ) Retrieved from http://www. usc. edu/dept/tsunamis/alaska/1958/webpages/lituyacloseup. html What causes tsunami? (n. d. ) Retrieved from http://beachsafe. org. au/tsunami/ema/pages/04_causes. html Cause of Tsunami (n. d. ) Retrieved from http://tsun. sscc. ru/tsulab/tgi_4. htm What causes Tsunamis? (November 12, 2012) retrieved from http://www. ga. gov. au/hazards/tsunami/tsunami-basics/causes. html