How Did A Tsunami Occur?

Introduction

Tsunamis or big waves themselves are large water waves caused by disturbances on the seabed, such as earthquakes. This disturbance then forms waves that spread in all directions with wave speeds reaching 600–900 km / hour. Initially, these waves have a small amplitude (generally 30–60 cm) so that they are not felt in the high seas, but the amplitude increases as they approach the shore. It is on reaching this coast that the tsunami sometimes hits the land as a giant wall of water (especially in large tsunamis), but the more common form is a sudden rise in the water level.
The rise in water levels alone can reach 15 to 30 meters, causing flooding with current speeds of up to 90 km / hour, reaching several kilometers from the coast, and causing considerable damage and casualties.

The process of a tsunami

is triggered by vertical movement of the plate in the form of a fault. The fault then causes the seabed to rise, which is called an earthquake. Well, from here the water balance doesn't move, causing a tsunami wave to hit the coast.
Although the main trigger for a tsunami is an earthquake, not all earthquakes will also end in a tsunami. Typically, only earthquakes above 7.0 on the moment scale have this potential. The stronger an earthquake, the greater the chance of a tsunami caused by the earthquake. The tsunami that occurred in Aceh is an example of a tsunami triggered by a large earthquake. At that time it reached 9.1 on the magnitude scale, and was the deadliest tsunami in history.

Apart from earthquakes, another common cause of tsunamis is landslides, which either occur under the sea or occur on land but move material such as rocks into the sea. Because underwater landslides often occur due to earthquakes, they can exacerbate disturbance to water after an earthquake. This phenomenon can cause tsunamis even in earthquakes of a magnitude that would not normally cause a tsunami (such as an earthquake with a magnitude slightly below 7.0), or cause a tsunami that is larger than expected based on the magnitude of the earthquake.

Another cause of a tsunami is volcanic activity, especially from volcanoes that are near or under the sea. Generally, volcanic activity causes the lips of a volcano to rise or fall, triggering a tsunami that is similar to an underwater earthquake tsunami. However, there can also be a large eruption that destroys a volcanic island in the middle of the sea, causing water to move to fill the island and initiating large waves.
In addition to the causes above, there are rarer causes of tsunamis, including the impact of a large object into the water due to a gun explosion or a falling meteor.