what is a tsunami, how is it formed and when was the last recent tsunami?

Question

When was the last tsunami and how does it happen ?

Answer 1

They are not tidal waves. Tidal waves happen twice a day when the tide goes in and out. A tsunami is caused by an underwater earthquake or major disturbance on the floor of the ocean. The last big one was on July 17th, 2006

Answer 2

A tsunami (not to be confused with tidal wave) is a large ocean wave, produced by an earthquake or a comparable disturbance of the sea floor (ie. landslides). Basically, the sea floor is moved or changed very quickly and a large wave is formed. Minor tsunamis happen everyday. In 2004, the biggest tsunami in recent history occured in the Indian Ocean.

Answer 3

A tsunami (pronounced /tsʊˈnɑːmi/ or /sʊˈnɑːmi/) is a series of waves created when a body of water, such as an ocean is rapidly displaced on a massive scale. Earthquakes, mass movements above or below water, volcanic eruptions and other underwater explosions, landslides and large meteorite impacts all have the potential to generate a tsunami. The effects of a tsunami can range from unnoticeable to devastating. The term tsunami comes from the Japanese language meaning harbour ("tsu", 津) and wave ("nami", 波). Although in Japanese tsunami is used for both the singular and plural, in English tsunamis is often used as the plural. The term was created by fishermen who returned to port to find the area surrounding their harbour devastated, although they had not been aware of any wave in the open water. Tsunamis are common throughout Japanese history, as 195 events in Japan have been recorded.

A tsunami has a much smaller amplitude (wave heights) offshore, and a very long wavelength (often hundreds of kilometres long), which is why they generally pass unnoticed at sea, forming only a passing "hump" in the ocean.

Tsunamis have been historically referred to as tidal waves because as they approach land, they take on the characteristics of a violent onrushing tide rather than the sort of cresting waves that are formed by wind action upon the ocean (with which people are more familiar). Since they are not actually related to tides the term is considered misleading and its usage is discouraged by oceanographers. [1] Since not all tsunamis occur in harbours, however, that term is equally misleading, although it does have the benefit of being misleading in a different language.

Causes
Tsunamis can be generated when the sea floor abruptly deforms and vertically displaces the overlying water. Such large vjafgbsdhjsfcxertical movements of the Earth’s crust can occur at plate boundaries. Subduction earthquakes are particularly effective in generating tsunamis. As an oceanic plate is subducted beneath a continental plate, it sometimes brings down the lip of the continental with it. Eventually, too much stress is put on the lip and it snaps back, sending shockwaves through the Earth’s crust, causing a tremor under the sea, known as an undersea earthquake.

Submarine landslides (which are sometimes triggered by large earthquakes) as well as collapses of volcanic edifices may also disturb the overlying water column as sediment and rocks slide downslope and are redistributed across the sea floor. Similarly, a violent submarine volcanic eruption can uplift the water column and form a tsunami.

Tsunamis are surface gravity waves that are formed as the displaced water mass moves under the influence of gravity and radiate across the ocean like ripples on a pond.

In the 1950s it was discovered that larger tsunamis than previously believed possible could be caused by landslides, explosive volcanic action, and impact events. These phenomena rapidly displace large volumes of water, as energy from falling debris or expansion is transferred to the water into which the debris falls. Tsunamis caused by these mechanisms, unlike the ocean-wide tsunamis caused by some earthquakes, generally dissipate quickly and rarely affect coastlines distant from the source due to the small area of sea affected. These events can give rise to much larger local shock waves (solitons), such as the landslide at the head of Lituya Bay which produced a water wave estimated at 50 – 150 m and reached 524 m up local mountains. However, an extremely large landslide could generate a megatsunami that might have ocean-wide impacts.

The geologic recorded tells us that there have been massive tsunamis in Earth's past. These tsunamis were so large that they caused landslides on the opposite coast triggering another massive tsunami or "bounce back" tsunami. An example today would be a landslide equivalent to everything west of Portland falling in to the Pacific ocean, resulting in a tsunami that hits the Chinese coast with enough force to erode the coast and trigger a landslide large enough to send a tsunami that would inundate the US west coast and wipe out Portland.

You could get more information from the link below...

Answer 4

NO, tsunami is reason whilst a huge quantity of water is being displaced, for this reason arising a sequence of waves this is invisible in deep ocean yet seen whilst the backside shallow out because of the fact the waves suggestions-set a shore line. for this reason ships in the midst of the sea does no longer additionally be tormented via those waves yet whilst the waves attain the shore, because of the sizeable volumes of water and the extreme kinetic potential, a tsunami can destroyed an extremely floor section.

Answer 5

A tsunami is a series of large waves. The last major one was this year in the Kuril Islands.

Answer 6

a tsunami is a giant wave/title wave that wipes out everything in its path!Its very frightening.Thailand had one last year.

Below are websites with pictures of tsunamis!

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Answer 7

Do you EVER watch the news?