George Jarka 3B

1. measures small changes in the magnetic feild
2. lowland between several highlands or mountain ranges created by the action of a geologic rift or fault
5. the theory that Earth's outer shell is divided into several plates that glide over the mantle
12. The greek word for "all the Earth"
13. a linear feature that exists between two tectonic plates that are moving away from each other.

1. Changes in direction or orientation of the magnetic field of the Earth that have occurred from time to time, about every 1000 years
3. the sideways and downward movement of the edge of a plate of the earth's crust into the mantle beneath another plate.
4. The process of the ocean floor moving away from an ocean ridge.
5. a strike-slip fault that offsets a mid-ocean ridge in opposing directions on either side of an axis of seafloor spreading.
6. Gravitational force that causes a plate to move away from the crest of an ocean ridge
7. The study of the magnetic record in rocks
8. an actively deforming region where two (or more) tectonic plates or fragments of the lithosphere move toward one another and collide.
9. a line on a diagram or map connecting points relating to the same time or equal time.
10. the portion of motion of a tectonic plate that can be accounted for by its subduction.
11. The hypothesis made by Alfred Wegner, that all continents use to be connected