<p> Chapter 19 - Earthquakes 19.1- Forces within Earth Earthquakes  Result of movement of crust produced by ______.  Stress = total ______acting on crustal rocks  Builds up ______ Overcomes strength of rocks and causes movement along ______in rock  Earthquake = ______caused by movement in crust</p><p>Stress  Three types  ______– decrease volume of material  Tension – pulls material ______ ______– causes material to twist</p><p> Strain = ______of material in a response to stress</p><p>Deformation  Elastic – when a material is______, bent, or stretched  at ______stress  Material can return to “______” when stress is zero  Example: Pulling on a rubber band</p><p>Deformation  ______– stress builds up past elastic limit  Permanent deformation – stays changed even when stress is ______ Point of Rupture = ______ Example: Pulling rubber band until it breaks</p><p>Deformation  Most materials exhibit varying degrees of plastic and ______deformation</p><p>Faults  Any fracture or system of fractures along which Earth moves  Happens along ______regions  Fault ______= surface along which movement takes place</p><p>Faults  ______Fault – form as a results of horizontal and ______compression that squeezes rock  Seen near ______plate boundaries  Two areas end up ______together after faulting</p><p> ______fault – movement partly horizontal and partly vertical  ______movement pulls rocks apart and stretches crust  Vertical movement causes one side of rock to move ______relative to the other side  Two areas end up ______apart after faulting</p><p> Strike-slip ______– caused by horizontal shear  Movement is mainly horizontal in opposite direction  Example: San Andreas Fault  Creates ______features after movement</p><p>Earthquake waves  ______waves = vibration of the ground produced during an earthquake  Primary waves = ______and push rocks in same direction wave is traveling  Secondary waves = cause rocks to move at ______angles relative to wave direction  Slower than ______waves  ______waves = cause most destruction and take longest to past  Slowest wave, only travel of Earth’s ______</p><p>Seismic Waves Earthquake  ______= point where waves originate  Epicenter = point on surface directly ______focus</p><p>In-Class Assignment/Homework 19.1 WKT</p>