Geography 1100 Lecture Notes - Lecture 5: Ground Vibrations, Wind Wave, Seismic Wave
11 Feb 2015
School
Department
Course
Professor
Document Summary
Earth sciences 1022b february 11 th lecture earthquakes. Cause: mainly by elastic- rebound of the crust as stress builds up as rocks bend, the stress builds up until they rupture and they start begin again or slip along the focus radiates in all directions. Occurs below the spot platted on a map called the epicentre and energy. Foreshocks and aftershocks accompany the main event with some earthquakes. Seismology: uses tremor -detecting seismographs to record vibrations as surface waves, and. Body waves (compressional and shear) that travel through rock: Surface waves : slowest, long l waves travel on the surface like ripples on water. Compressional : push-pull - faster, primary p waves travel in the direction of initiation, like a. Shear : slower, secondary s waves travel perpendicular to the direction of initiation, moving slinky rope up and down. Seismic stations around the world indicate that earthquakes occur mainly at plate boundaries and are shallow, intermediate, deep (>300m); shallow most destructive.
