EPSC 201 Lecture Notes - Lecture 9: Mantle Plume, Richter Magnitude Scale, Convection
11 Mar 2013
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Document Summary
Earthquakes pick out the boundaries of the tectonic plates, zones of spreading and subduction quite accurately. An upward push of the mantle causes the crust to crack. The oceanic crust is quite thin; about 6- The dots on the figure below indicate earthquakes. Pushing the brittle crust downwards causes it to fracture and break. Anywhere these fractures oc- cur, there is a potential for deep focus earthquakes. Here is a map of the tectonic plates. There is and equal amount of subduction and spreading, which keeps the size of the earth constant. The age of the mined by the mag- ridge is the striping. The rock nearest the mid ocean can be deter- rock netic youngest, and it gets older moving out- wards. Obviously, it would be very difficult to obtain rock samples from under the oceans; however, it is easy to drag a magnetometer across the ocean.
