g10.   What are earthquakes?

Earthquakes are a shaking of the earth caused by waves traveling away from a disturbance. The place where the faulting begins within the earth is the focus. The point on the earth's surface directly above the focus is the epicenter. The S-waves are the first to leave.  They are the second fastest.  These waves move horizontally. The P-waves are compressional and travel the fastest. The L-waves are the slowest.  They travel over the surface, doing the most damage. These are vertical waves. Earthquake waves slow down as they travel through different media.  The molten outer core deflects them. Earthquakes are closely associated with ridges and trenches.

m12.    Why are organisms becoming extinct?

m41.    How can matter affect the environment?

m66.    How can risks be analyzed?

m74.    How is soil important in the environment?

m78.    How do droughts and floods impact populations?