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Ch. 5 Earthquakes
Question | Answer |
---|---|
seismology | the study of earthquakes |
seismograph | instrument used to record seismic waves |
seismogram | tracing of seismic waves by a seismograph |
seismic waves | waves of energy that travel through the Earth |
body waves | seismic waves that travel through the Earth's interior |
surface waves | seismic waves that travel along the earth's surface |
P Waves | -fastest -first to arrive -pressure waves -travels through solids, liquids, and gas |
S Waves | -second to arrive -shearing waves -only travels through solids |
Earthquake Hazard | how prone an area is to experience an earthquake |
How is an area's EQ Hazard Level determined? | by the area's past and present seismic activity |
S-P time method | used by seismologists to determine an EQ's epicenter |
epicenter | the location on the Earth's surface, directly above the focus, where an EQ occurs |
focus | location within the Earth where an EQ occurs |
How many seismograph stations are required to find an epicenter and why? | 3, because one will give too many possibilities, two narrows it to two possible epicenters and three pinpoints the exact location |
Moho | point between the crust and mantle where seismic waves speed up |
shadow zone | place on the Earth's surface where no seismic waves from a specific EQ can be detected -lead to the discovery of a liquid outer core |
gap hypothesis | the theory that areas along an active fault line that have little seismic activity will be the locations of future earthquakes |
seismic gaps | locations along an active fault line with little seismic activity |
fault | a break in the Earth's crust |
strongest earthquakes usually occur deep within the earth at what type of boundary? | Convergent |
elastic rebound | when rock breaks and immediately snaps back to its original shape -the direct cause of EQs |
elastic deformation | when rock bends and breaks elastically, causes EQs |
plastic deformation | when rock bends and stays bent, does not cause EQs |