| A | B |
|---|
| fault | crack in the earth's crust |
| magnitude | strength of an earthquake |
| earthquake | the surface of the earth shifting |
| magma | molten rock below the earth's surface |
| seismograph | a written record of magnitude |
| Richter Scale | unit for magnitude |
| three | most earthquakes are < this on the Richter Scale |
| tectonic plate boundaries | where most earthquakes and volcanoes occur |
| thirty two | Richter Scale factor |
| seismogram | machine that records magnitude |
| deformation | change in rock caused by the stress of pulling, pushing or twisting |
| elastic rebound | when rock or plates spring back after being pulled or pushed out of position |
| seismology | the study of earthquakes |
| seismologist | one who studies earthquakes |
| transform plate motion | creates strike-slip faults |
| convergent plate motion | creates reverse faults |
| divergent plate motion | creates normal faults |
| earthquake zone | an area where lots of earthquakes occur |
| S waves | slower, secondary, transverse |
| P waves | faster, primary, longitudinal |
| surface waves | the ones that cause damage to our cities |
| epicenter | surface above the quake |
| focus | the first point along the fault where motion occurs |
| S-P time method | a way of finding the epicenter |
| intensity | a measure of the feeling of the quake and the damage |
| earthquake hazard | how likely it is that a quake will happen in your area |
| seismic gap | an area on a fault with few earthquakes |
| gap hypothesis | a prediction that a large quake will occur in a seismic gap |
| flexible structures | more earthquake proof |
| brick buildings | more likely to be destroyed |
| fire and floods | secondary effects of an earthquake |
