Earthquake and Tsunami

EARTHQUAKE

We all know an earthquake is. Remember our beloved country, Indonesia has had many earthquakes recently, Yogyakarta, Pangandaran, Padang, and even Jakarta, the capital city, were not free from earthquakes.

An earthquake is the result of a sudden release of energy in the Earth’s crust that creates seismic waves. What’s that? Seismic waves are the waves of energy which are caused by the sudden breaking of rock within the Earth or an explosion. In its most generic sense, the word earthquake is used to describe any seismic event-that whether a natural phenomenon or an event which is caused by mostly rupture of geological faults, volcanic activities, landslides, mine blasts, and nuclear experiment.

Seismology is the study of earthquakes and seismic waves that move through and around the Earth. A seismologist is a scientist who studies earthquakes and seismic waves. Our country needs many seismologists, because it lies on the tectonic plate where earthquakes may often occur. Do you want to be a seismologist???

TSUNAMI

Tsunami is a Japanese word which means “harbor wave.” A tsunami is a very long-wavelength wave of water. It is produced by a sudden displacement of the seafloor or disruption of any body of big water. Tsunamis are sometimes called “seismic waves” because they are caused by earthquakes. There are also other causes of tsunami such as under sea tectonics, eruptions, landslides, underwater explosions, and meteorite impacts. These forces will make two split giant waves. One goes to the middle of the ocean and the other to land. Tsunamis do not always produce big waves that break up along the shore. But, they will cause powerful waves with high speed. These make high tides throughout the sea surface in a sudden.

(Source : Buku Siswa SAINS, MODUL SAINS SMP-SBI kelas VIII, page 313-314 and 324)