Outline for class: Thursday, 11 February
Topic: Crustal Mobility: the Evidence
Class Activities:
- Review of hydrothermal vents---hot water vents at mid-ocean
ridges.
- Submersibles are used to carry people to the seafloor for
observations; the deepest submersible is a Japanese model that
can go into the deepest trenches. Remotely-operated vehicles
(ROVs) are operated from a ship or land and carry cameras so
that people at the surface can see what the seafloor looks like.
- Review of features on the seafloor; see list of some geographic
features on page 7 of the course reader.
- Exercise 2 images and questions: (1) How do earthquakes correspond
with ocean floor features; (2) Which depths correspond with which
features.
- Question for 3x5 card: What experience have you had with
earthquakes; what is actually happening to generate earthquakes?
- Earthquakes occur when stresses (pressure) builds up to the
point that the strength of rocks are overcome and two pieces
of rock slide past each other. The sliding action generates seismic
waves that travel through the earth. The waves travel by vibrating
the earth material through which they pass.
- Students simulate seismic waves by generating "P"
waves (compressional waves that vibrate parallel to their direction
of motion) and "S" waves (shear waves that vibrate
perpendicular to their direction of motion).