Plates tectonic locationsofearthquakes

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Unformatted text preview: ocated using three seismographs Earthquake Belts Earthquake 95% of energy released by earthquakes originates in narrow zones that wind around the Earth around These zones mark of edges of These tectonic plates tectonic Locations of earthquakes Locations of earthquakes 80% of seismic energy around from 1980 to 1990 Pacific Rim Broad bands are subduction zone earthquakes, narrow are MOR Depths of Earthquakes Depths Earthquakes originate at depths ranging from 5 to nearly 700 kilometers nearly Definite patterns exist Definite – Shallow focus occur between mid-ocean ridges – Deep earthquakes occur in Pacific landward of oceanic Deep trenches trenches – Central continent (intraplate) earthquakes are of Central various causes. Some causes still uncertain. various Devastating earthquakes occur less than 60 kilometers because cold rock is more elastic, and transmits waves better than warmer rocks below transmits Earthquake Depth and Plate Tectonic Setting Weakest are the divergent zone earthquakes Strongest Here Strongest, with worst Subduction Zones discovered by Benioff Tsunamis, at entrance to subduction zones Earthquakes in subduction Earthquakes in subduction zones Recent example, 9.0 Christmas 2004 Earthquake and Tsunami, Sumatra Earthquakes at Divergent Boundaries ­ Iceland A new graben, down dropped hanging wall block ­ Normal Fault – divergent zone MOR Measuring the size of Measuring the size of earthquakes Two measurements describe the size of an Two earthquake...
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This document was uploaded on 01/26/2014.

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