What is a tsunami geography?
A tsunami is a large sea wave caused by the displacement of a large volume of water. They can be caused by earthquakes triggered by moving sections of the Earth’s crust under the ocean. In the last decade there have been a number of devastating tsunamis.
How are tsunamis formed a level geography?
Tsunami are generated when a sub-marine earthquake displaces the sea bed vertically as a result of movement along a fault line at a subduction zone. The violent motion displaces a large volume of water in the ocean water column, which then moves outwards from the point of displacement.
How are tsunamis formed GCSE geography?
Most tsunamis are caused by earthquakes at destructive plate boundaries . Here, an oceanic plate is subducted into the mantle beneath a continental plate. This movement causes friction, which in turn causes the plates to stick. Energy accumulates, like that of a compressed spring.
What is tsunami look like?
They more likely resemble a very rapidly rising tide with the cycle occurring in just 5 to 60 minutes instead of 12 hours with potentially much greater height. Occasionally, tsunamis can form walls of water (known as tsunami bores) but tsunamis normally have the appearance of a fast-rising and fast-receding flood.
How does a tsunami look?
What does a tsunami look like when it reaches shore? Normally, a tsunami appears as a rapidly advancing or receding tide. In some cases, a wall of water or series of breaking waves may form.
What is a tsunami ks4?
Tsunamis. A tsunami is a huge wave, usually caused by volcanic or earthquake activity under the ocean, which can eventually crash onto the shoreline. The effects on a community can be devastating. Geography.
What causes tsunamis?
Tsunami can be caused by sub-marine earthquakes at subduction zones as a result of sea-bed and water column displacement. 2004 Indian Ocean – 9.2 – 24 m wave height – 230,000 deaths 2006 Java – 7.7 – 2-6 m – 800 dead 2009 Samoa – 8.1 – 14 m – 190 dead 2011 Japan – 9.0 – 9.3 m – 16,000 dead
What are the characteristics of tsunamis?
Tsunami characteristics are very different from those of wind-generated ocean waves: wave heights are typically less than 1 m wavelengths are usually more than 100 km speeds are 500-950 km/h In the open ocean tsunami are barely noticeable. As the waves approach shore they slow dramatically, wavelength drops but wave height increases.
How do Tsunamis affect the coastlines?
Tsunami usually hit coastlines as a series of waves (a ‘wave-train’) in an effect which is more akin to a flood than a breaking wave. Sub-marine earthquakes that occur close to shorelines can generate intense ground shaking damage, followed by damage from the subsequent tsunami.
What is the wavelength of a tsunami wave?
wave heights are typically less than 1 m wavelengths are usually more than 100 km speeds are 500-950 km/h In the open ocean tsunami are barely noticeable. As the waves approach shore they slow dramatically, wavelength drops but wave height increases.
How are tsunamis formed geography?
Tsunami are waves caused by sudden movement of the ocean surface due to earthquakes, landslides on the sea floor, land slumping into the ocean, large volcanic eruptions or meteorite impact in the ocean.
What is it called when a tsunami hits the shore?
Potentially imperceptible in deep water, a tsunami increases in height as it encounters the shallow waters of shore, often leading to extensive wreckage and loss. process where a storm or tsunami causes the sea to rush inland, as a storm surge. Also called estuarine flooding.