By Ryan Quinn

 When earth quakes happen they cause movements or vibrations. A fault line is a crack in the ground that forms mountains, plains, rivers, and valleys. The tectonic plates are beneath the earths crust sometimes they move a continent one centimeter a year. A seismograph is a machine used to tell how big the earth quake is.

Seismic waves are primary waves, surface waves, and secondary waves

WWhat’s inside earth is the crust, mantle, outer core and the inner core

Called P waves they are the fastest waves of all primary waves travel through solids, liquids, and gasses they are also the fist to arrive at a distance point

Called L waves they are the slowest waves of all they cause the most damage they are felt at the surface

Tectonic plates are under the earths crust and can move a continent about one centimeter a year.

Secondary waves are also called S waves. They travel through solids only. They are slower than Primary waves, and arrive first to arrive at a later distance point.

A seismograph is a instrument that scientist use to measure how big the earth quake is

Earth quakes are disasters. The tectonic plates push the ground to crack and that makes an earth quake. There was one earth quake in San Francisco that wiped out the whole city in 1906

 A fault line is a crack in the earths crust that causes earth quakes and forms mountains, plains, volcanoes and valleys

We live on it! The crust is