In Indonesia, we are very familiar with the word ” Tsunami “. This natural disaster has ever killed thousands of lives in Banda Aceh a few years ago. Indonesia mourned, the world mourned. Then, how the Tsunami happens and what is the Tsunami ? Here is a brief explanation of Tsunami.

               Tsunami is a term derived from Japanese, consisting of two words “tsu” and “nami”, each of which means “port” and “wave”. Meanwhile, scientists interpret it as “tidal waves” (tidal waves) or ocean waves due to earthquakes (seismic sea waves).

               Tsunamis are large ocean waves that come quickly and suddenly crashing into the coastal area. The waves are formed due to the activity of the earthquake or Mount which erupts under the sea. The magnitude of the tsunami waves caused flooding and damage when it hit the coastline.

    The formation of tsunamis occurs when the surface of the sea floor rises and falls along the fault during the earthquake. The fault caused disruption of sea water balance. Large faults will also produce large wave power. Moments after the earthquake, the water recedes. After receding, sea water returned to the mainland in the form of large waves. In addition, the formation of the tsunami was also caused by the eruption of Mount Merapi on the ocean floor. The eruption caused a high movement of sea water or surrounding waters. The bigger the tsunami, the greater the flood or damage that occurs when it hits the coast.

               The speed of a tsunami wave is greater than a normal wave in general, that is, it can go up to 700 km / hour, almost equivalent to the speed of an airplane. This speed will decrease as the tsunami waves enter the shallow sea, but the wave height will increase. The tsunami wave height is generally 50 to 100 meters and spreads in all directions. In addition, the height of the tsunami wave is also affected by the shape of the coast and its depth. Earthquakes on the ocean floor have the potential to create tsunamis that are dangerous to humans.