Earth Science Chapter 19 Earthquake notes

Earth Science - • S shaped wave moving from side to side • Slower reaches epicenter after P waves 3 Surface Waves • Caused by interaction of

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Chapter 19 Earthquakes Section 1 Earthquakes What causes earthquakes? Plates slide past each other creating friction. The friction builds up until the plates slip. Focus = source of earthquake (inside earth) Epicenter = point directly above earthquake on the surface. Intensity = size/strength of earthquake Seismograph = instrument that measures strength of an earthquake. = zigzag reading is a seismogram Three seismographs can be used to pinpoint the epicenter of an earthquake. (Triangulation) Magnitude = intensity Measured by Richter Scale (1-10) Each number is 32 times stronger than previous number. Earthquake Waves 1. Longitudinal Waves / Primary (P) Wave originate from the earthquake’s focus compress the earth in front of the wave fastest moving wave; reaches epicenter first 2. Transverse Waves / Secondary (S) Waves Originates from the earthquake’s focus
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Unformatted text preview: • S shaped wave moving from side to side • Slower; reaches epicenter after P waves 3. Surface Waves • Caused by interaction of P & S waves. • Causes the surface to roll. • Originate from epicenter; not focus. • Most destructive Section 2: Folds, Faults, and Mountains Folding- bending rock Two types: 1. Anticlines 2. Synclines (sink) Fault- joint, or crack in rock. Types: 1. Normal Fault • Caused by tension • Hanging wall drops below footwall. Footwall Hanging wall • Forms fault block mountains 2. Reverse Faults • Caused by compression • Hanging wall moves up in relation to footwall. • Forms oversthrust mountains Hanging wall Footwall 3. Lateral Faults • Caused by shearing (sliding in opposite directions) • Causes friction • Earthquakes are common • San Andreas Fault...
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This note was uploaded on 12/25/2011 for the course GEOG 123 taught by Professor Mitchelle during the Fall '10 term at Everglades.

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Earth Science - • S shaped wave moving from side to side • Slower reaches epicenter after P waves 3 Surface Waves • Caused by interaction of

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