Earthquakes and Volcanoes Study Guide

Faults  Normal Fault:  Plate boundary- divergent  Stress- tension  Reverse Fault:  Plate boundary- convergent  Stress- compaction  Strike-slip Fault:  Plate boundary- transform  Stress- shear

Seismic Waves  P waves:  Primary waves  Come first  Back and forth motion  Travel through Solids and Liquids  S waves:  Secondary waves  Sideways or side to side motion  Travel through solids only  Surface waves:  Waves on Earth’s surface  Cause the most damage  Circular movement

Focus/Epicenter  Focus:  Starts deep within the earth along the fault line  Right where the rupture occurs  Epicenter:  Point directly above the focus, on the surface of the Earth

Hot Spots  Areas on Earth’s mantle where high temperature causes sections of Earth to rise  Heat melts the rock that is forced to the surface  Form away from plate boundaries  Examples: Hawaii, Yellowstone

Composite Volcano  Eruption:  Alternate between explosive and non-explosive eruptions  Sometimes runny lava, sometime pyroclastic material type lava  Wide base/steep sides  Most dangerous  Alternate between explosive and non-explosive eruptions  Most dangerous

Cinder Cone Volcano  Smallest, but most explosive  Lava that breaks up and shoots into the air (pyroclastic material)  Magma is viscous  Most common volcano

Shield Volcano  Very wide, but shallow/gradual slope  Runny lava  Non-explosive  Get their name from a warriors shield  Ex: Mt. Eta