Science Ch. 6 Keyterms

1. The point beneath Earth’s surface where rock breaks under stress and causes an earthquake.
4. The force that opposes the motion of one surface as it moves across another surface.
6. A device that records ground movements caused by seismic waves as they move through Earth.
7. A scale that rates earthquakes by estimating the total energy released by an earthquake.
8. A scale that rates an earthquake’s magnitude based on the size of its seismic waves.
10. An earthquake that occurs after a larger earthquake in the same area.
11. A type of fault where the hanging wall slides downward; caused by tension in the crust.
14. A type of fault in which rocks on either side move past each other sideways with little up or down motion.
16. Stress that pushes masses of rock in opposite directions, in a sideways movement.
17. A type of seismic wave that forms when P waves and S waves reach Earth’s surface.
18. The process by which an earthquake’s violent movement suddenly turns loose soil into liquid mud.
20. A type of fault where the hanging wall slides upward; caused by compression in the crust.
22. A downward fold in rock formed by compression in Earth’s crust.
24. Stress that squeezes rock until it folds or breaks.
26. A force that acts on rock to change its shape or volume.

2. The record of an earthquake’s seismic waves produced by a seismograph.
3. The block of rock that forms the upper half of a fault.
5. A building mounted on bearings designed to absorb the energy of an earthquake.
7. A scale that rates earthquakes according to their intensity and how much damage they cause at a particular place.
9. The shaking that results from the movement of rock beneath Earth’s surface.
12. The block of rock that forms the lower half of a fault.
13. Stress that stretches rock so that it becomes thinner in the middle.
15. A type of seismic wave that compresses and expands the ground.
19. The point on Earth’s surface directly above an earthquake’s focus.
21. An upward fold in rock formed by compression of Earth’s crust.
23. A large wave produced by an earthquake on the ocean floor.
25. The measurement of an earthquake’s strength based on seismic waves and movement along faults.
27. A type of seismic wave that moves the ground up and down or side to side.