Earthquakes essays

Earthquakes essays The earth we live on consists of the ocean, and the continents. Below the ocean and continents we have the earths crust, which can very in length for miles. Under the earths crust we encounter small breaks in the earth, which is caused by the slow movement of mantle. With this movement we find the plates of the continent breaking apart and causing earthquakes (Nicholls, Bill 2). The earths mantle roughly extends about 1,798 miles. The density of the mantle changes because of pressure and heat. The further down the mantle is the more pressure and heat we encounter (Nicholls, Bill 1). The worlds lithosphere covers the entire earth (outer shell) and can be broken in many places to form what is called plates. These continental and oceanic plates are constantly moving and they never stop. With the concurrent movement of our lithosphere many mountains, volcanoes, and earthquakes will be created because of these plates (Spall, Henry 1). Oceanic plates can also cause earthquakes. Although it seems odd we encounter earthquakes, under water they still occur. Small narrow ridges within the seafloor are cracking because the crust is in constant motion, and with constant motion the oceanic crust is breaking away. Volcanic eruptions from the earths mantle will eventually fill these cracks and form a replaceable crust (Spall, Henry 1). Below the earths crust we have what is called a magnetic field, which is created by the solid form of basaltic. Basaltic is a magnetized material that has reversed the earths polarity 170 different times within the last 80 million years. With the magnetic field being in occurrence this can aid plate tectonics into an earthquake (Spall, Henry 2). In our world we have what is called major crustal plates we now know that there are seven major crystal plates, subdivided into a number of smaller plates (Spall, Henry 2). The small plates are ab...