What Causes a Tsunami

Tsunami is a seismic sea wave that is often caused by earthquakes, when the tectonic plates beneath the ocean floor collide with each other. These earthquakes may sometimes not cause a tsunami themselves, but may subsequently lead to one, as a result of oceanic landslides.

These landslides cause huge masses of water to rise above the surface line, which form into giant waves within the shallow water of shorelines. A strong volcanic eruption can also lead to a tsunami.

Oceanic earthquakes are by far the most common cause of tsunami. The reason being, the tectonic plates under the ocean floor sometimes rub or collide against one another, which causes a lot of energy to disperse.

The heat, energy, and pressure exerted from below, causes large volume of water to surge. To make it clearer, what actually occurs during an under ocean earthquake is, the heavier tectonic plates try to slide their way from under the lighter tectonic plates.

These plates are basically made up of condensed rock-like matter that move along the asthenosphere, which is a partially molted and weaker version of the mantle. These tectonic plates are also known as litospheric plates.

Tsunamis occur when the heavier tectonic plate gets stuck with the lighter one, which leads to massive pressure built up while the heavier one pushes the lighter plate sideways and downwards. What happens next is that, when the lighter plate reaches its limit of being pulled downwards, it suddenly snaps to its original surface area, thereby causing pressure to explode upwards. This pressure pushes the water upwards and forms into a humongous wave.

Tsunamis can be so powerful that they can travel over many thousands of kilometers, just to crash at the shores. Most tsunamis occur in the pacific ocean, which is also the biggest water body on Earth. It covers 1/3 rd of the Earth's surface area, and is surrounded by deep oceanic trenches, island arcs, and mountainous landscape. Which is why this area is often called the 'Ring of Fire' because it is prone to earthquakes.

With about 2/3 rd of the world being ocean, the consequences of a strong oceanic earthquake can be catastrophic. An example of the effects of tsunami, being the Christmas tsunami that hit the Indian ocean in 2004. This earthquake originated from the islands of Sumatra and had a magnitude of 9.2 on the Richter scale.

This earthquake caused a string of tsunamis that swept across Indonesia, India, Madagascar, and was even felt in parts of Ethiopia! It was the worst tsunami of modern times and claimed more than 283,000 lives. It also completely destroyed landscapes along with buildings and other standing objects.

A massive meteoric impact and nuclear testing of weapons underwater in the ocean, can also cause tsunamis. Scientists have not yet come up with a way to prevent tsunamis from occurring, though, certain measures have been taken that allow us to predict whether a tsunami is approaching a specific group of areas through satellite identification and reading of oceanic waves.