The Cause of The Tsunami

Tsunamis can occur if an interruption occurs that causes the movement of large amounts of water, such as volcanic eruptions, earthquakes, landslides or meteorite that fell to earth. However, 90% of the tsunami is an earthquake under the sea. In recording the history of some of the tsunami caused by the volcano eruption, for example when the eruption of Mount Krakatoa.
Vertical movement on the earth's crust, can lead to the ocean floor rise or drop suddenly, which resulted in disruption of water balance that is above them. This resulted in the energy flow of sea water, which when it reached the coast into a large wave that caused the tsunami. 

Tsunami formation

The speed of tsunami waves depends on the depth of the sea where the waves occurs, where the speed can reach hundreds of kilometers per hour. When the tsunami reaches the shore, its speed will be around 50 km / h and its energy is very damaging coastal areas in its path. In the midst of the tsunami wave height sea only a few centimeters to several meters, but when it reaches shore wave height can reach tens of meters due to a buildup of the water. When the tsunami reaches the coast of the mainland will crawl away from the coastline with a range of several hundred meters can even be a few kilometers.
This vertical motion can occur on the earth fault or the fault. The earthquake also occurred in the subduction area, where the oceanic plate menelusup down the continental shelf.
The landslide that occurred on the seabed and volcanic debris can also lead to disruption of sea water which can generate a tsunami. The earthquake caused perpendicular movement of the earth layer. As a result, the sea rose and fell abruptly so that the balance of sea water which is above them disturbed. Similarly, cosmic objects or meteor that fell from above. If the size of a meteor or landslide is big enough, can occur megatsunami reach hundreds of meters high. 

Terms of the tsunami caused by the earthquake
* An earthquake centered in the middle of the sea and shallow (0-30 km)
* An earthquake with a strength of at least 6.5 on the Richter Scale
* An earthquake with a pattern of reverse fault or fault down