| A | B |
|---|
| Sedimentary rock | layered rock containing fossils |
| igneous rock | volcanic rock |
| metamorphic rock | rock changed by heat and pressure |
| shearing | force that moves blocks of rock past each other |
| tension | force that pulls rocks apart |
| compression | two forces push against rock layers from oposite sides |
| earthquake | shaking of the earth's crust |
| bench mark | mark made on a permanent object to see if the earth's crust has moved |
| tiltmeter | instrument that measures the tilting of the earth's surface |
| folded mountains | fromed from compression |
| fault-block mountain | fromed from shearing |
| seismic wave | vibrations of the earth's surface |
| epicenter | place on the earth's surface directly above the focus |
| seismograph | instrument used to record seismic activity |
| P-waves | seismic waves that cause the rocks in the earth to vibrate back and forth |
| S-waves | seismic waves that cause rocks in the earth to vibrate up and down |
| L-waves | seismic wves that move along the surface to the earth |
| Richter scale | determines the magnitude of an earthquake |
| ring of fire | area where many earthquakes and volcanoes occur |
| cinder cone | violently erupting volcano |
| shield cone | lava flows periodically from a volcano's vent |
| composite cone | volcanoes that alternate between being quiet and being violent |
| dormant | a volcano that has not shown any activity for a long time |
| extinct | volcano that has not erupted for thousands of years |
| plate tectonice | theory that the earth's crust is divided into several moving plates |
| pangaea | giant land mass that existed when all the continents were together |
