EARTHQUAKES. What is an Earthquake?. Sudden movement in the Earth’s crust that releases energy as vibrations, or waves . Movement occurs along areas of weakness in the earth’s crust Elastic Rebound Theory – tension or stress, elastic displacement, release. Elastic Rebound.
Location where the actual slippage or
Crack in the crust along
which movement occurs
in the samemedium, P waves travel at a greater velocity (speed) than S waves. However, the velocities of seismic waves depend upon the physical properties of the material through which the waves travel (medium). Higher density media result in a higher velocity of wave propagation.
Mount St. Helens, Washington Seismogram, Station CPW, May 18, 1980 (located 70 miles northwest)
Off the coast of Honshu, Japan March 12, 2011 9.0
Miyako Surge – coastal fishing city
Miyagi Surge – 6 miles inland
4. Before and after aerial slides