NATS 1750 Lecture Notes - Lecture 8: Foreshock, Logarithmic Scale, 32X
Document Summary
All faults have to be described in terms of dip and strike angles. Since earth"s plates are always in motion, this will have effects on its surface. As these plates move, rock moves against rock. Although we give spreading or movement rates (these are averages), the motion is not necessarily smooth. Earthquakes result when large volumes of rock move suddenly and rapidly. Earthquakes occur along fault lines where the stresses have ruptured the earth"s crust. 95% of earthquakes occur along the circum-pacific belt (ring of fire) Earthquakes can occur where new faults are forming and where pre-existing faults exist. Large earthquakes tend to happen on their own by themselves. Earthquakes are associated with faults, volcanoes and plate boundaries (these are all potential sources of earthquakes) Earthquakes can only occur up to 800km deep as at that point the mantle becomes plastic and you won"t feel the earthquake.