Earthquakes are a result of motion within the earth.
This only occurs where the earth is solid and therefore can only occur within about 100 miles of the surface
Earthquakes provide the best evidence regarding the interior structure of the Earth.
Tidal waves or Tsunamis result when a large section of the sea floor
suddenly moves and therefore displaces a massive amount of water.
Tidal waves or Tsunamis result when the low amplitude long wavelength waves
reach the shallow shoreline and begin to feel the bottom of the sea floor. This
Shortens the wavelength and increase the amplitude (height).
Location of worldwide earthquakes
Earthquakes by depth.
Notice that the deep earthquakes occur only at subduction zones.
Our first evidence of tectonic motion is based on similar fossils and
rock types on opposing sides of the ocean
Today plate boundaries are determined by examining
the location of volcanoes and earthquakes.
Volcanoes result from the friction (heat) of the plates