Teks Tentang Tsunami (In English)

Tsunami

            Tsunami is a natural disaster caused by the increasing waves of the sea to land with a high swiftness as the consequence of the quake which is centred under the ocean. The quake can be caused by land erosion, sifted plate, an erupted volcano as well as a meteoroid that falls in the ocean. Tsunami usually happens if the size of the earthquake exceed until 7 on the Richter scale. This tsunami is quite dangerous, mainly for those who live around the beach. With great force, it will sweep out whatever around it. From all causes of tsunami, earthquake is the major cause.

            An earthquake on the bottom of sea gives rise to an affliction of the sea water that caused by the change of the profile of the ocean floor that generally occurs because of a tectonics earthquake and perpendicular (vertical) ground motion with the surface of the sea water or earth surface. If the movements of the ground are horizontal on the surface of the sea, there will not happen tsunami.

            Even though the movement of the ground is horizontal, but the energy of the earthquake is big, and it can cause the collapse of cliffs/hill on the sea automatically in which the movement is perpendicular to the surface of the sea. Although there is no earthquake that hits the land directly which results vertical movement, the condition of a cliff and hill in the sea has been unstable and because of the force of gravity and ocean currents that led to landslides, it causes tsunami.

            Earthquake causes perpendicular layers motion of earth. As a result, the sea bottom is suddenly up and down, so that the balance of sea water was disturbed on it, similarly with cosmic objects or meteors that fall from above. If the size of a meteor or landslide is quite big, megatsunami can happen with hundreds of meters high.

            Vertical movement of the earth crust because of a volcanic eruption, an earthquake, the avalanche or a meteor falling to earth can cause the sea floor becomes up or down suddenly therefore it disturbs the balance of water on it. This makes the occurrence of energy flow of sea water on the beach become large waves so that tsunami happens. Billows can spread to all directions. Energy which conceives in the wave of the tsunami is fixed on the function of the altitude. The height of waves in the sea is only about 1 meter. Thus, the rate of a wave cannot be felt by a ship that was in the middle of the sea. When it approaches the coast, the speed of the tsunami of decline until about 30 miles per hour, but its height has increased to reach tens of meters. When it reaches the coast, tsunami enters the land until hundreds of meters, even kilometres.

            The victim of tsunami is not a little. The casualties are hit by sluggish water flow and material that carried away by the tsunami. Besides the victim, tsunami also has a negative impact on the building, herbs, and pollution to agricultural land, and water.