Tsunamis are series of the ocean waves with very long wavelengths, hundreds of kilometers away, being brought about by various processes like sub marines, landslides, glacier calving, volcanic eruptions, meteorite impacts but greatly by earthquakes. It is formed in the ocean and big lakes.
Tsunami originated from the Japanese words ‘tsu’ meaning ‘harbor’ and ‘nami’ meaning ‘wave’ to make a ‘harbor wave’. Tsunamis have in the past and present brought catastrophic devastation to property and human death like in North East of Japan, on March 11, 2011. We shall dwell on the Shifts in the Tectonic plates as the reasoning behind the Tsunamis, but we have to understand the concept involved in the movement of the plate tectonics then how the earthquake will be generated to result into tsunami.
These are movements of the lithospheric plates. Tectonics is movement and deformation of the crust, which integrate the ancient theory of continental drift. Plates are the “lithospheric plates which are about 100 kilometers or more” (Earth Quake Museum, 2011, p. 1). Plate tectonics mostly produces earthquake.
It should be noted that, “the earth crust consist of plates sections that float on the molten rock of the mantle” (Earth Quake Museum, 2011, p. 1). The movement of the plates is due to the conventional current. Conventional current is brought about by relationship between the densities of the fluid to its temperature. We can say that convectional current is the flow that transfers heat within a fluid by setting in motion by the heating and cooling of the fluid which changes in its density and continues as long as it heats.
The magma containing material at very high temperatures “rises and spreads on the surfaces creating a new crust which spreads out forming a new plate, until it meets other plates” (Earth Quake Museum, 2011, p. 1). After such a mechanism, “then one of the plates will pushed down into the inferior of the earth and reabsorbed in the mantle; plates can also compress to push up the mountains when they collide or move sideways along the transform faults” (Earth Quake Museum, 2011, p. 1).
The process of plates’ movements is a bit detailed as explained by the Geography site below:
One of the most famous examples of plates sliding past each other is the San Andreas Fault in California. Here the two plates, the Pacific plate and the North American plate both move in a roughly in the northwesterly direction, but one is moving faster than the other. The San Francisco area is prone to many small earthquakes every year as the two plates grind against each other. (Geography site, 2006, p. 1)
The above diagram shows, “Divergent Boundaries occur at Oceanic Ridges, where new Oceanic lithosphere is formed and moves away from the ridge in opposite directions” (The Earth and Beyond, 2011, p. 1).