Tsunami is one of the natural disasters which are very dangerous for coastal areas. From Japanese Tsunami is translated as “big wave in the harbor” and should be determined properly as marine gravity waves that are created as a result of shifting up or down of the seabed, during underwater and coastal earthquakes. According to Levin (2008) the average speed of tsunami is from 50 to 1000 km / h. Also the average height or elevation of tsunami wave is averaging from 0.1 to 5 m in occurrence area to almost 10 to 50 m at coastal area. Tsunami often produces huge destruction on the land. For many years this unbridled natural phenomenon keeps people in fear and forced them to create a lot of legends about these killer waves. Also it is important to notice that tsunami isn’t a single wave, it is a series of waves coming ashore one after another. Their number varies from 3 to 25. But not every wave is a tsunami. Storm waves, a wave from ship or others are just a movement of only top layer of the water, while tsunami is a movement of all water depth.
Background of the tsunamis
Tsunamis are often caused from underwater earthquakes. Seaquakes are not the only causes of tsunamis; also they can be caused by different typhoons, tropical cyclones, landslides or underwater volcanic eruptions. The biggest waves are formed in contact between water and cosmic body: a comet or meteorite. The consequences of such catastrophe are really hard to imagine. According to Stain (2004) some scientists suppose that even the dinosaurs died due to the crash with cosmic body that forced tsunamis. The earthquake should be very powerful, lightning-fast and large enough to drive the water column. In addition, the earthquake shouldn’t be too deep (max 20 km depth). Therefore, not every earthquake at the ocean bottom creates a giant wave Past/historical tsunamisIt is a popular myth that tsunamis are occurring only in warm seas. But this information is fake. Yes, most of the tsunamis occur in the Pacific Ocean, where there are a lot of seaquakes or active underwater volcanoes. Japan and the Pacific Islands often suffer from tsunamis. Speaking about landslide tsunamis we should notice that they are forced by the collapse of rocks sea cliffs and it is almost impossible to predict their affect. For example, in 1964, as a result of the earthquake and subsequent ice collapses a huge tsunami occurred in Alaska. The height of waves was above 60 meters!
Before the beginning of the tsunami the water recedes from the shore. According to Koeberl (2002) the recedes of the water depends on the length of the tsunami. This idea is quite innovative, because years ago scientists thought that the level of water recedes depends on the power of tsunami.At first, talking about this natural phenomenon, we should observe that in fact the height of a tsunami depends on its energy. The farther distance from the epicenter of the tsunami, …