ATOC 185 Lecture Notes - Lecture 2: Hypocenter, Richter Magnitude Scale, Seismic Wave
30 Dec 2016
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Document Summary
Our ability to predict earthquakes is very poor. When earth crust breaks quickly is causes earthquakes and cracks brittle (closer to earth"s surface) When the crust breaks deeper down earthquakes don"t usually occur, the crust just bends (ductile deformation) Scientists judge the strength of earthquakes by how long they last. Gutenberg-richter relationship shows that globally, small earthquakes are much more common than large ones. Stress builds up in the crust and is relieved by earthquakes. The larger the earthquake, the larger the amount of time between another earthquake. Sometimes an earthquake can start a chain reaction of earthquakes in the area. Almost all the action takes place over plate boundaries. Different types of plate boundaries: spreading centre- divergent boundary. Magma pushes two plates apart and creates new material that adds on to the plates. The melted magma pushes up and creates earthquakes. There is a clear association with volcanoes and earthquakes.
