| Introduction:when a body of water, such as an | | | | pile up to form tremendous crests, in an |
| ocean is rapidly displaced on a massive scale | | | | effect known as "shoaling". |
| then we call it tsunami. It Is a series of | | | | |
| waves. The effects of a tsunami can range | | | | Signs of an approaching tsunami: |
| from unnoticeable to devastating. There are | | | | |
| various reasons behind the tsunami. | | | | 1.An earthquake may be felt. |
| | | | |
| 1.earthquakes. | | | | 2.Large quantities of gas may bubble to the |
| | | | water surface and make the sea look as if it |
| 2.mass movements. | | | | is boiling. |
| | | | |
| 3.Volcanic erosions. | | | | 3.The water in the waves may be unusually |
| | | | hot. |
| 4.Under water explosions. | | | | |
| | | | 4.The water may smell of rotten eggs or of |
| 5.Meteorite impacts. | | | | petrol or oil. |
| | | | |
| The term tsunami comes from the Japanese | | | | 5.A thunderous boom may be heard then a a |
| language meaning harbour. tsunami is used for | | | | roaring noise as of a jet plane or a |
| both the singular and plural. The term was | | | | whistling sound. |
| created by fishermen. | | | | |
| | | | 6.The water may sting the skin. |
| Causes: | | | | |
| | | | 7.A flash of red light might be seen near the |
| 1.it happens when the sea floor abruptly | | | | horizon. |
| deforms and vertically displaces the | | | | |
| overlying water. | | | | 8.The sea may recede to a considerable |
| | | | distance. |
| 2.it also happens because of the large | | | | |
| vertical movements of the Earth's crust can | | | | Warnings and prevention: |
| occur at plate boundaries. | | | | |
| | | | Tsunamis cannot be prevented or precisely |
| 3.Subduction earthquakes are particularly | | | | predicted |
| effective in generating tsunamis. | | | | |
| | | | 1.Regions with a high risk of tsunamis may |
| 4.too much stress is put on the lip and it | | | | use tsunami warning systems to detect |
| snaps back, sending shockwaves through the | | | | tsunamis and warn the general population |
| Earth's crust, causing a tremor under the | | | | before the wave reaches land. |
| sea, known as an Undersea Earthquake. | | | | |
| | | | 2.Computer models can roughly predict tsunami |
| 5.Sub-marine landslides and collapses of | | | | arrival and impact based on information about |
| volcanic edifices may also disturb the | | | | the event that triggered it and the shape of |
| overlying water column. | | | | the seafloor and coastal land. |
| | | | |
| 6.violent submarine volcanic eruption can | | | | 3.the early warnings comes from nearby |
| uplift the water column and form a tsunami. | | | | animals. |
| | | | |
| Tsunami wave: | | | | 4.building tsunami walls of up to 4.5 m (13.5 |
| | | | ft) high in front of populated coastal areas. |
| The ocean waves are divided into three | | | | |
| groups. They are characterized by depth. | | | | 5.floodgates and channels to redirect the |
| | | | water from incoming tsunamis. |
| 1.Deep water. | | | | |
| | | | 6.Environmentalists have suggested tree |
| 2.Intermediate water. | | | | planting along stretches of sea coast which |
| | | | are prone to tsunami risks, it would take |
| 3.Shallow water.tsunami waves are considered | | | | some years for the trees to grow to a useful |
| shallow-water waves. As the wave approaches | | | | size. And such plantations could offer a much |
| the shallow waters of shore, its time period | | | | cheaper and longer-lasting means of tsunami |
| remains the same, but its wavelength | | | | mitigation. |
| decreases rapidly, thus causing the water to | | | | |