| A | B |
|---|
| stress | force actng on a material |
| strain | the deformation of a material in response to stress |
| fault | system of fractures where movement occurs |
| primary wave | runs parallel to the direction of the wave; penetrates Earth's core |
| secondary wave | runs perpendicular to the direction of the wave; the second to arrive |
| surface wave | the most dangerous of the seismic waves |
| focus | the place where an earthquake originates |
| epicenter | on the surface, above the focus of an earthquake |
| seismogram | a record of plate movement that results in an earthquake |
| magnitude | the amount of energy released during an earthquake |
| Richter Scale | measures earthquake intensity by measuring the size of the largest seismic wave |
| tsunami | large ocean waves produced by the vertical motion of the ocean floor - produced by earthquakes |
| seismic gap | sections of faults that have not been seismically active in a long time |
