Evidence Paper
Name: Andy Cheung
Class: K
Subject: Earth Science
The formation of the Earth is a mysterious. However, Earth’s structure is a common knowledge. Plate tectonics is the theory that the outer layer of the earth (the lithosphere) is divided into a couple of dozen "plates" that move around across the earth's surface. The formation of earthquakes and tsunami is related to the Theory of Plate Tectonics. Tectonic plates map draws the general outline where the earthquakes and tsunami occur the most.
Earthquake is one of the most destructive natural disaster. However, earthquakes are only occur in certain area with certain conditions. The area has to located either in between two tectonic plates or in fault zone. For the tectonic plates, earthquake is caused by transform boundary. When two tectonic plates slide along each other, It releases energy in waves. It also knowns as earthquake. Here is an example of transform boundary earthquake. The strongest and most famous earthquake along the San Andreas fault hit San Francisco in 1906. Many buildings were shaken to pieces by the quake, and much of the rest of the city was destroyed by the fires that followed. More than 600 people died as a result of the earthquake and fires.
On the other hand, earthquake is also caused by sudden slip on a fault. Stresses in the earth's outer layer push the sides of the fault together. When rocks slip suddenly, it releases a energy in waves that travels through the earth’s crust. Here is an example of normal fault earthquake. The earthquake that happened in the New Madrid area along the Mississippi River was a big earthquake in early 1800s. The magnitude of the earthquake ranged from 6.7-8.8. The number of lives lost from the earthquake remains unknown.
Tsunami is another form of earthquake. However, tsunamis are happened in the mid-ocean. Tsunamis are caused landslide. Rockfalls or icefalls landslides can generate displacement of water to create a tsunami. Landslide-induced tsunami is the example of landslide tsunami. It caused by the movement of a significant amount of earth for the construction of an airport, which resulted in destructive tsunami waves hitting the harbor of Thebes.
Seismic waves waves also known as earthquake waves. These waves caused earthquakes and tsunamis. These waves are P wave, S wave and L wave. P wave moves from side to side. S wave moves up and down. L wave moves in all directions. Scientists are used these waves to measure the magnitude(size) of earthquake based on Richter Scale. Seismograph is the tool to measure the magnitude of earthquake.
In conclusion, the Theory of Plate Tectonics explains the causes of earthquakes and tsunami. The Theory of Plates Tectonics divided the Earth into couple plates. According to the evidence above, earthquakes and tsunami mostly occur between two plates. They are mostly caused by transform boundary. San Francisco is one of the city where earthquakes happen frequently because It is located close between two tectonic plates.
Sources
"New Madrid Earthquakes of 1811-12 | United States." Encyclopedia Britannica Online. Encyclopedia Britannica, n.d. Web. 03 Apr. 2015.
