GEO 1111 Lecture Notes - Lecture 8: Shear Modulus, Bulk Modulus, Seismic Wave

• School: University of Ottawa
• Department: Geology
• Course: GEO 1111
• Professor: Robert Jack Cornett

Document Summary

Seismic waves can be measured using sensitive pendulums (seismometers) The pendulum stays put as the ground moves allowing it to draw out the p-waves (small when drawn), s-waves (lightly larger) and the surface waves (largest) Developed in 1935 to quantify and compare quake magnitudes. Two things used to determine magnitude of quake on scale: the amplitude of largest wave (maximum amplitude, the distance of the seismometer to the epicentre (determine from. Determining location of epicentre requires multiple stations. Since p-waves travel faster, they arrive before s-waves. Their interval increases with distance from epicentre. Their spread is called the p-s time interval, used to locate epicentre. Help determine composition of earth: low-density mantle, high-density core. Seismic velocity increases with rigidity of solid, and rigidity increases with depth. Increase in density reduces velocity of p- and s-waves. Rigidity: measure of how difficult a solid is to shear and compress. Seismometers who don"t receive s-wave signals from quakes are in the.