GEOL 240Lg 1st Edition Lecture 8 Outline of Last Lecture I The three principle stresses II Definition of total stress III Maximum Compressive Stress IV Normal Fault V Reverse Faults VI Strike Slip Faults VII Principal stress planes VIII Thrust Planes Outline Current Lecture I Review Stresses II Plate tectonic III Elastic Rebound Theory IV Energy in rocks V States with major earthquakes Current Lecture What is the orientation of sigma 3 Horizontal Sigma 2 vertical Plate tectonic Energy causes tectonic stresses that causes earthquakes Elastic Rebound Theory explains in detail where the energy comes from that are responsible for generating earthquakes Elastic strain energy professor is demonstrating with a long stick and bending it and pushing against his fingers he said it pushes back against your finger Professor is pretending to bend a rock He explains that rock shares elasticity so when he bends it the rock actually does bend slightly This means that that rock and rocks underneath are feet are atoms and many more bending which disturbs Professor is pulling the rubber band and he says he is winding the clock therefore storing more energy to it Rocks are elastic we bend the rocks because the plates are moving causes an enormous amount of energy One of the all time great earthquake photos 2010 Greendale Present Configuration of the Pacific North American plate boundary Major western cities at seismic risk LA thrust strike slip faulting San Diego Strike slip faultingSeattle WA Subduction earthquakes thrust faulting Mount St Helens 1980 Eruption landslide followed by blast due to pressure release Explosion caused by the gasses trapped magma being clogged North south crustal shortening in WA has produced E W folds in the south central state below We want to focus on the Seattle area Bainbridge Island LIDAR GPS Global positional system Who paid for the GPS satellite department military usage designed originally for military usage When two plates converge towards each other and if the interface between them is locked the upper plate must blackboard Measurements of coastal uplift from the southern part of Vancouver slide JAN 26 1700 around 9ish During an earthquake all the energy that has been stored up by the relative
View Full Document
Unlocking...