EESA06H3 Lecture : Lecture 2
Document Summary
Most faults are locked and then they snap. Surface waves keep to the earth s surface but go around the entire planet. y body waves go all the way down through the earth interiors across the entire planet. y y p and s waves in body waves. Primary (p) and secondary (s). y compressional waves are the quickest. Move through materials through alterative compression and extension. Called primary wave because during an earthquake they are first to arrive. y rocks are alternatingly being stressed and compressed. y second waves are smaller at about 5km/second. E. g: creating a wave with a rope. y seismograph is an instrument like a telegraph. Slabs of oceanic crust going down 100 km back into the mantel. y deep and intermediate earthquakes are tracking friction that is produced by slabs going down with depth. 700km down. y descending slabs are not brittle but soft and started melting.
