| A | B |
|---|
| seismology | the study of earthquakes |
| seismologist | a person who studies eartquakes |
| fault | a break in the Earth's crust in which plates slide past one another |
| deformation | a change in the shape of rocks due to stress |
| plastic deformation | rocks act like a piece of molded clay; does NOT cause earthquakes |
| elastic deformation | rock stretches and snaps back like a rubber band; this causes earthquakes |
| elastic rebound | sudden return of elasticall deformed rock back to its original shape |
| Transform plate motion | causes a strike slip fault |
| Convergent plate motion | causes a reverse fault |
| Divergent plate motion | causes a normal fault |
| earthquake zone | a place where a large number of faults are located |
| seismic waves | waves of energy that travel through the Earth |
| body waves | P waves and Swaves are a type of these |
| survace waves | waves of energy that travel along the Earth's surface |
| pressure waves | P waves or primary waves |
| shear waves | S waves or secondary waves |
| P waves | seismic wave that causes rock to move in a back- and- forth direction |
| S waves | seismic wave that causes rock to move in a side-to-side direction |
| seismograph | an instrument that records vibrations in the ground and determines strength and location of an earthquake |
| seismogram | a tracing of earthquake motion that is created by a seismograph |
| epicenter | point on the earth's surface diectly above an earthquakes starting point |
| focus | the point along a fault at which the first motion of an earthquake occurs; it is inside the Earth |
| S-P time method | a method for finding the epicenter of an earthquake |
| Richter Magnitude Scale | used to measure strength of a quake |
| magnitude | a measure of the strength of a quake |
| intensity | measure of the degree to wich an earthquake is felt and the damage that it causes |
| Mercalli Intensity Scale | used to measure damage caused by an earthquake |
| earthquake hazard | measure of how likely an area is to have a damaging earthquake in the future |
| gap hypothesis | says that a major earthquake is more likely to occur along a path of an active fault where no earthquakes have occured for a period of time |
| seismic gap | an area where few earthquakes have occured recently, but |
| retrofitting | the process of making older structures more earthquake resistant |
| mass damper | weight on the roof of a building |
| active tendon system | found at a lower level in a building. works like a mass damper. |
| base isolators | act like shock absorbers, they absorb seismic waves so they do not travel through the building |
| cross braces | placed between the floors of a building;counteract pressure that pulls and pushes through a building |
| flexible pipes | prevent waterlines and gas lines from breaking |
