TUGAS BAHASA INGGRISTUGAS BAHASA INGGRISEXPLANATION TEXT : EXPLANATION TEXT :

TSUNAMITSUNAMI

Oleh: Oleh: FIKRI DINULMAULA (8)FIKRI DINULMAULA (8)

Kelas : XII IPA 2Kelas : XII IPA 2SMA NEGERI 2 MATARAMSMA NEGERI 2 MATARAM

SUBTITLESUBTITLE

Tsunami Tsunami Description :Description :

1.1. The General of TsunamiThe General of Tsunami2.2. What causes of Tsunami?What causes of Tsunami?3.3. Where do tsunamis occurs in the Where do tsunamis occurs in the

worldworld

The General of TsunamiThe General of TsunamiTsunami is a Japanese word meaning ‘harbor Tsunami is a Japanese word meaning ‘harbor

wave’. It is constituted with two syllables, Japanese wave’. It is constituted with two syllables, Japanese language meaning harbour ("tsu", language meaning harbour ("tsu", 津津 ) and ) and wave ("nami", ("nami", 波波 ).).

Tsunami is a wave train or series of waves Tsunami is a wave train or series of waves generated, by impulsive disturbance that vertically generated, by impulsive disturbance that vertically displaces the water column, in water body. Earthquake, displaces the water column, in water body. Earthquake, landslides, volcanic eruption, explosion and even the landslides, volcanic eruption, explosion and even the impact of cosmic bodies like meteorites commonly impact of cosmic bodies like meteorites commonly generate tsunami. Tsunami savagely attacks coastlines generate tsunami. Tsunami savagely attacks coastlines causing devastating property damage and loss of lives.causing devastating property damage and loss of lives.

Tsunami "Wave Train"Tsunami "Wave Train"Many people have the mistaken belief that tsunamis Many people have the mistaken belief that tsunamis

are single waves. They are not. Instead tsunamis are "wave are single waves. They are not. Instead tsunamis are "wave trains" consisting of multiple waves. The chart below is a trains" consisting of multiple waves. The chart below is a tidal gauge record from Onagawa, Japan beginning at the tidal gauge record from Onagawa, Japan beginning at the time of the 1960 Chile earthquake. Time is plotted along the time of the 1960 Chile earthquake. Time is plotted along the horizontal axis and water level is plotted on the vertical axis. horizontal axis and water level is plotted on the vertical axis. Note the normal rise and fall of the ocean surface, caused by Note the normal rise and fall of the ocean surface, caused by tides, during the early part of this record. Then recorded are tides, during the early part of this record. Then recorded are a few waves a little larger than normal followed by several a few waves a little larger than normal followed by several much larger waves. In many tsunami events the shoreline is much larger waves. In many tsunami events the shoreline is pounded by repeated large waves.pounded by repeated large waves.

1.1. Tsunami can be Tsunami can be generated when the sea floor abruptly when the sea floor abruptly deforms and vertically deforms and vertically displaces the overlying displaces the overlying water. water.

2.2. Tectonic earthquakes are a Tectonic earthquakes are a particular kind of particular kind of earthquake that are earthquake that are associated with the earth’s associated with the earth’s crustal deformation, when crustal deformation, when these earthquakes occur these earthquakes occur beneath the see, the water beneath the see, the water above the deformed area is above the deformed area is displayed from its displayed from its equilibrium position. equilibrium position.

3.3. Waves are formed as the Waves are formed as the displaced water mass, displaced water mass, which acts under the which acts under the influence of gravity, influence of gravity, attempts to regain its attempts to regain its equilibrium equilibrium

What Cause of TsunamiWhat Cause of Tsunami

Most tsunamis are caused by earthquakes generated Most tsunamis are caused by earthquakes generated in a in a

subduction zone, an area where an oceanic plate is subduction zone, an area where an oceanic plate is being being

forced down into the mantle by plate tectonic forces. forced down into the mantle by plate tectonic forces. The The

friction between the subducting plate and the friction between the subducting plate and the overriding overriding

plate is enormous. This friction prevents a slow and plate is enormous. This friction prevents a slow and steady steady

rate of subduction and instead the two plates become rate of subduction and instead the two plates become "stuck". "stuck".

Subduction Zones are Potential Tsunami LocationsSubduction Zones are Potential Tsunami Locations

As the stuck plate continues to descend into the As the stuck plate continues to descend into the mantle mantle

the motion causes a slow distortion of the overriding the motion causes a slow distortion of the overriding plage. plage.

The result is an accumulation of energy very similar The result is an accumulation of energy very similar to the to the

energy stored in a compressed spring. Energy can energy stored in a compressed spring. Energy can accumulate in the overriding plate over a long accumulate in the overriding plate over a long

period of period of time - decades or even centuries.time - decades or even centuries.

Accumulated Seismic EnergyAccumulated Seismic Energy

Energy accumulates in the overriding Energy accumulates in the overriding plate until it exceeds the frictional forces plate until it exceeds the frictional forces between the two stuck plates. When this between the two stuck plates. When this happens, the overriding plate snaps back into happens, the overriding plate snaps back into an unrestrained position. This sudden motion is an unrestrained position. This sudden motion is the cause of the tsunami - because it gives an the cause of the tsunami - because it gives an enormous shove to the overlying water. At the enormous shove to the overlying water. At the same time, inland areas of the overriding plate same time, inland areas of the overriding plate are suddenly lowered. are suddenly lowered.

Earthquake Causes TsunamiEarthquake Causes Tsunami

Tsunamis occur most frequently in the Tsunamis occur most frequently in the Pacific Ocean, but , but are are

a global phenomenon; they are possible wherever large a global phenomenon; they are possible wherever large bodies of bodies of

water are found, including inland lakes, where they can water are found, including inland lakes, where they can be caused be caused

by landslides. by landslides. Japan is a nation with the most recorded tsunamis in Japan is a nation with the most recorded tsunamis in the the

world. The earliest recorded disaster being that of the 684 world. The earliest recorded disaster being that of the 684 A.D. A.D. Please refer to the below website of the List of historic Please refer to the below website of the List of historic

tsunamis by death tolltsunamis by death toll

Where do tsunamis occurs in the Where do tsunamis occurs in the worldworld

Map of tectonic plates where the earthquake triggered Map of tectonic plates where the earthquake triggered the tsunamithe tsunami

Tsunami is one of the earth’s disaster. It was a Japanese word Tsunami is one of the earth’s disaster. It was a Japanese word meaning “harbor wave,” used as the scientific term for a class meaning “harbor wave,” used as the scientific term for a class of abnormal sea wave that can cause catastrophic damage when of abnormal sea wave that can cause catastrophic damage when it hits a coastline. it hits a coastline. Tsunamis can be generated by an undersea earthquake, Tsunamis can be generated by an undersea earthquake, an undersea landslide, the eruption of an undersea volcano, an undersea landslide, the eruption of an undersea volcano, or by the force of an asteroid crashing into the ocean. or by the force of an asteroid crashing into the ocean.

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