Translations:Adventist Youth Honors Answer Book/Nature/Geology - Advanced/2/en

2. Provide the following information:

a. How do earthquakes tell us what the interior of the earth is like?

Earthquakes show us that faults are active and moving. Faults are boundaries between the tectonic plates that make up the Earth's crust. Earthquakes generally happen along faults. The plates move apart or alongside one another releasing energy that causes an earthquake. The energy released causes seismic waves. In fact the core of the earth was discovered with seismic waves. They bend along the interfaces of different materials. There are two different seismic wave types. P waves travel through fluids and solids. S waves travel only through solids. By noticing that the S waves did not go through the center of the earth, geologists came to the conclusion that its center must be a fluid, for S waves cannot pass through fluids. P waves bend in the core because they are slowly passing through a liquid. This has also helped them estimate the size of earth’s core by studying the last shadow zone of the S wave.