How earthquakes happen?

1 ANSWERS

1. Guest3205
   

   In order to know the process of happening of earthquakes we first need to know the structure of earth. The earth can be divided into three main layers: the outermost crust, middle mantle and innermost core (inner and outer core). The crust and the upper mantle of the earth form a strong layer called the lithosphere. This strong lithosphere is further broken down into plates called tectonic plates. Thus, the earth's crust is not actually one thick blanket, instead it's something like a puzzle, with pieces coming together to form one picture. The size of these pieces or plates can vary from a few hundred to thousands of kilometers across while the thickness may vary from less than 15 km to 200 km. When these plates underline the oceans, they are termed as oceanic plates, whereas when they underline the continents, they are referred to as continental plates.

   
   

   
   
   When the mantle within the earth's crust moves in the deeper part of the earth, the plates begin to move as well. They begin to pull away from each other, bump into one another or slide past one another. This movement of plates is quite slow almost the same speed as how our fingernails grow. It's when these plates collide against each other that rock layers are forced upwards in the form of mountains. When these plates move away from one another, lava from the mantle fills the gap and forms new crust. These plates also converge over a period of thousand years by slowly positioning them one beneath the other. Earthquakes occur at the edges of the plates, and more commonly at the edges of large plates forming the earth's crust.
   
    

   Report (0) (0)  |   12 years, 8 month(s) ago