Why tsunamis form

Underwater, landslides are often similar to volcanoes that avalanche into the sea. This process happens as a result of an earthquake, so in a way, the main source is still an earthquake. However, earthquakes can also merely loosen landmass which starts falling at some later point. Volcanoes can form tsunamis through two mechanisms. Either they collapse or they eject matter with such strength that they uplift the water.

In the first case, land-based volcanoes can also cause tsunamis, if they are very close to the sea. The meteorite works in pretty much the same way, except it creates huge ripples.

This kind of tsunamis are really rare, but there is an instance in where such a wave was created by rockfall in Lituya Bay, Alaska. Join the ZME newsletter for amazing science news, features, and exclusive scoops. More than 40, subscribers can't be wrong. Tsunamis are not always colossal waves when they come into the shore.

Rather, they come in much like very strong and very fast tides i. By now, you should have a pretty clear idea why tsunamis are so dangerous. They can be very long kilometers is a reasonable length , very high the Japan tsunami measured over 10 meters and can travel extremely fast without losing much of their energy. An earthquake far into the ocean can send several devastating tsunamis hundreds or even thousands of kilometers away. In , an earthquake with the epicenter off the west coast of Sumatra, Indonesia struck with a magnitude of 9.

The Indian Plate was subducted by the Burma Plate and triggered a series of devastating tsunamis, some over 30 meters high. The tsunamis killed over , people in 14 countries, being one of the biggest natural disasters in human history. It is just one in many tragic examples highlighting the sheer force of tsunamis. Since science cannot predict when earthquakes will occur, we cannot determine exactly when a tsunami will be generated.

Their force has to be sufficient enough to cause the displacement of such a huge amount of water as is present in a large water body. While a tide also causes the formation of a series of waves, the scene varies in case of tsunamis. A regular tide may not cause destruction.

On the other hand, a tsunami is highly destructive to property and lives. At times, tsunamis occur in such bad forms that they take away entire cities along with their waves.

They do not lose their intense energy even after crossing vast oceans. Thus, you can imagine the force generated by earthquakes or volcanoes that leads to unlimited destruction in the form of tsunamis. Your email address will not be published. Save my name, email, and website in this browser for the next time I comment.

Why Do Tsunamis Form. Related Articles. But large events like the earthquake and tsunami in Chile in and the recent Japanese disaster have put tsunamis back into the public consciousness. Though they have occurred through history, their unpredictability and infrequency makes them difficult to study.

Scientists know what causes them and, following the advent of tsunami warning centres, can measure how fast they travel and when they may reach distant shores. But because each tsunami is unique and not all earthquakes produce them, there is still little known about where the worst waves will strike and how big they will be.

Related story: 10 most destructive tsunamis in history. Underwater volcanoes erupting, icebergs calving and in rare instances meteorites hitting the ocean have all produced the giant waves in the past. But very large underwater earthquakes are responsible for about three-quarters of all tsunamis.

This is largely because of the same principal as to why shallow earthquakes, like the Christchurch one, cause so much damage: a large amount of energy has a shorter distance to travel and less resistance to travel through. But the earthquake that size off the coast of Japan last week was only 24 km below the ocean floor. Most normal ocean waves have a wavelength the distance between crests of consecutive waves of at most 30 to 40 m, but tsunamis are completely different, says Dale.

Once a tsunami has been generated, scientists can accurately forecast the when to within a couple of minutes and the where it will hit coastline. Prior to the tsunami, though, there was no tsunami warning centre in the Indian Ocean, so warnings issued were slow or non-existent. To track tsunami wave movements, scientists rely on a series of complex monitoring systems, starting with devices on ocean floors that are able to measure an increase in pressure at that point.

This information is sent to buoys on the surface, which is passed to satellites and then to monitoring stations on land. Despite this, it is difficult to forecast how the wave will behave on arrival.

Amazing video of the Japan tsunami.