GEOL 106 Lecture Notes - San Andreas Fault, Silly Putty, Plate Tectonics
4 Mar 2013
School
Course
Professor
Document Summary
Transform fault margins under water, in the mid-atlantic ridge. Right angle cracks: like ripping news paper. Two plates are sliding against each other an rubbing. In between the two plates = transform margin: ex. 1% of earthquakes occur not at plate margins: intraplate earthquakes, most are along former plate margins: rivers are often faults ex. Epicentres of earthquakes are down the river. The rivers used to be plate margins because during. Pangea, a bunch of cracks opened up in 3s, forming rivers. Failed arm: one of the 3 cracks that failed to open up. Still potentially prone to earthquakes: 20,000 years ago there were ice sheets covering continents, ex. Canada, which caused stress: 12,000 years ago, the ice sheets were lifted up, causing readjustment and potential cracks, knowing plate boundaries is important for seismic risk. 90% at depths less than 100 km: constructive margin, collision of plates in the subduction zone, on transform faults.
