A tsunami is defined as a sequence of waves caused by eruptions of volcanoes undersea and earthquakes. Tsunamis form when there is an unexpected movement of gigantic masses of water caused by landslides, eruptions of volcanoes and earthquakes on the sea bed.They are usually small and hardly ever noticed in deep oceans.It is estimated that 86% of all tsunamis are caused by what is called seaquakes (Grossman 1).For tsunamis that are caused by seaquakes, three things need to take place and they include the following; lowering or lifting of the sea bed by an earthquake. If the displacement of the sea bed occurs sideward, there will be no tsunami will happen. This is similar to what took place when Western coast of Sumatra experienced an earthquake on the 28 March, 2005. Secondly, the epicenter of the earthquake must be adjacent to the surface of the globe. Thirdly, the earthquake must be at least measure 7, 0 on the Richter scale.It is from this intensity that energy is released leading to the movement of water resulting in the creation of a tsunami.
Tsunamis happen because of any disruption that transfers anenormous mass of water from its equilibrium point. Geological processes for instance landslides, earthquakes, and eruptions of volcanoes cause tsunamis. They happen in three phases and they include the generation phase that describes the causes of tsunamis, the propagation to the coast, and the run-up at the shoreline (Grossman 1).
The generation phase explains the various ways through which tsunamis can happen and they include the following;
For a volcano to produce a tsunami, a volcano must be close to the coast. Secondly, there must be an eruption that sends large enough amounts of material into water to relocate asubstantial quantity of water. The breakdown and fall of a volcano on land can force large quantities of debris and ash into the water. This unexpected change of the water column changes to Kinetic energy and creates waves. Hugeamounts of debris can result in a rise in wave amplitude. Conversely, submarine volcanoes can also induce tsunamis. The submerged volcanoes can fall hence heating the nearby water very fast.
An eruption of a volcano can create a small earthquake that can make a tsunami to happen. Volcanoes with Plinian activity are characterized by massive destructive explosions and resultant collapse of a caldera can generate giant waves.History shows that there are various examples of volcanic tsunamis for instance; the collapse of a caldera of the Volcano Santorini during a key eruption 3500BP resulted in a huge tsunami.
Prior to the occurrence of an earthquake, the Indian-Australian plane pushes itself into the Eurasian plate. The meeting of the plates results in tension in rocks. During the occurrence of an earthquake, the vast tension at the edge of the plate becomes loose and goes back to its original position. The tensions which haveinitially been built up over several years result in unexpected movement which can be considered an earthquake.Secondly, when an earthquake occurs, the displaced and transferred water leads to the establishment of waves. The movement of water into shallow waters in the coastal region contributes to a rise in amplitude. Nonetheless, if an earthquake takes place away from a water body, it does not disturb water and as a result, no tsunami is anticipated.
Tsunamis can also take place because of landslides. There are two types of landslides that can make tsunamis to happen and they include the coastal and underwater landslides. There are a number of mechanisms that can speedy these landslides. Slopes found in the coastal area are subjected to various erosion forces because of sea waves, rainfall, and storms. This results into considerable amount of rocks, debris, and sand to fall over the nation resulting in a perturbation of the surface of the sea and eventually resulting in a tsunami (Grossman 1).
Meteors further explain how tsunamis happen. Research showsthat comets, asteroids, and meteorites can result in catastrophic events if they run into with the earth (Grossman 1). Tsunamis are the sternest type of damage caused by stony asteroids if they bump intothe earth. A study to find out how meteoroids results in tsunamis indicated that an asteroid whose diameter is 5km falling in a mid-Atlantic lead to generation of tsunamis that inundate the upper two thirds of the Eastern US.There are other causes of tsunamis for instance atmospheric processes.
After the formation of a tsunami, the wave system highly bears a resemblance to throwing a stone into a pond. Quite a few minutes after the generation process, the original tsunami is classified into a tsunami that travels towards the closest sea and the other travels into the deep ocean.
In the propagation to the coast, the speed of the tsunami reduces as it travels into shallower waters and its height increases. There are various events that come about as the tsunami travels over the continental slope and the obvious on is increase in amplitude (Grossman 1)
The run-up of tsunamis take place when tsunami waves travel from a continental slope region that contain deep waters to a region that is close to the shore.After a run-up, part of the tsunami energy is diverted back to the open to the open ocean. Additionally, a tsunami can create a specific category of wave known as edge waves. These waves travel in parallel directionsto the shore. The effects lead to certain arrivals of waves at a specific point on the coast. The behavior of a tsunami when close to the coast makes the first run-up of the tsunami not to be large. A strange behavior happens in the sea when near the shore regions. Various sets of condition are applicable in shallow water close to the shore when a tsunami is submerging the coast.
In conclusion, tsunamis are natural catastrophes caused by volcanoes, earthquakes, landslides, and meteors that creates disturbance in a mass of water bringing about a series of waves.They happen in three phases and they include the generation phase that describes the causes of tsunamis, the propagation to the coast and the run-up at the shoreline. The formed waves travel close to the coastal areas causing a rise in height with a reduction of their velocity, resulting in destructions when the tsunami approaches the shoreline. However, it is significant to carry out more research in order to understand the impacts and how tsunami’s.There is a need for more research to be done to determine factors that contribute to the generation of tsunamis.
Grossman, Zoltan. “Tsunami – How A Tsunami Happens”. Academic.evergreen.edu. N.P., 2016. Web. 10 Sept. 2016.