Tsunami and
Earthquake
1.Tsunami
The term tsunami comes from Japanese,
‘Tsu’ means harbor
and ‘nami’ means
wave. Then, tsunami is mean waves
that hit the harbor.
Tsunami is a great sea wave produced by a submarine earthquake, volcanic eruption, or large landslide. The displacement of the sea floor that occurs during certain large submarine earthquakes and landslides causes displacement of large volumes of the sea water above it producing large, fast moving waves.
Tsunami mainly cause by landslides on the sea floor, seafloor volcanic eruption, or due to rare meteor. A tsunami cannot be precisely predicted, even if the magnitude and location of an earthquake is known. However, there are some warning signs of an impending tsunami, and automated systems can provide warnings immediately after an earthquake in time to save lives. One of the most successful systems uses bottom pressure sensors, attached to buoys, which constantly monitor the pressure of the overlying water column.
The example of tsunami:
· 24 December 2004 in Aceh-INDONESIA
· 11 March 2011 in JEPANG
· 27 October 2010 in Mentawai-INDONESIA
· 17 July 2010 in Pangandaran-INDONESIA
Sources:
2. Earthquake
an earthquake (also known as a quake, tremor or temblor) is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity seismic or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time. Earthquakes are measured using observations from seismometers.
Tectonic earthquakes occur anywhere in the earth where there is sufficient stored elastic strain energy to drive fracture propagation along a fault plane. The sides of a fault move past each other smoothly and aseismicallyonly if there are no irregularities or asperities along the fault surface that increase the frictional resistance.
There are three main types of fault that may cause an earthquake:
a. A strike-slip earthquake
b. A normal earthquake
c. A thrust earthquake
The objective of earthquake engineering is to foresee the impact of earthquakes to minimize the risk of damage. Existing structures can be modified by seismic retrofitting to improve their resistance to earthquakes. Earthquake insurance can provide building owners with financial protection against losses resulting from earthquakes. Emergency management strategies can be employed by a government or organization to mitigate risks and prepare for consequences.
There are some effects of earthquakes:
· Shaking and ground rupture
· Landslides and avalanches
· Fires
· Soil liquefaction
· Floods and Tsunami
· An earthquake may cause injury and loss of life, road and bridge damage
Sources:
created by Nisa Aulia Paramitha
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