- 31.7: the number of times greater energy an earthquake w/ one # greater magnitude releases than the lower
- active tendon system: a weight in the building's base, similar to the mass damper
- base isolators: these are in the base of the building; made of rubber w/ a lead core; absorb seismic waves to avert their travel through the building
- body waves: seismic waves that travel through the Earth's interior
- convergent boundaries: strong and deep earthquakes occur here
- cross braces: steel braces in between the floors that support the building during earthquakes
- divergent boundaries: weak and shallow earthquakes occur here
- earthquake hazard: measures how vulnerable an area is to future earthquakes
- elastic rebound: this causes earthquakes; the ground suddenly retains original shape
- epicenter: the ground directly above where the earthquake occured
- focus: the direct area of seismic activity
- gap hypothesis: the theory that areas where few earthquakes have occured are likely to experience aerious quakes in the future
- marsquakes: some earthquakes, though seismographs often acted more like a wind gauge because of the wind
- mass damper: a weight in the building roof that will counteract w/ building movement when activated
- moho: seismic waves travel much faster upon reaching this area
- moonquakes: seismic waves last much longer than they do on Earth
- P-waves: move back and forth; fastest; can travel through all material
- Ritcher scale: tool used for measuring earthquake strength
- S-P time method: the common method used to find an earthquake's epicenter
- S-waves: move like a snake; second to arrive; cannot go through liquid mass
- seismic gap: a particular area along a seismic-active location where unusually few earthquakes have occured
- seismogram: a recording of the shaking motion in earthquakes
- seismograph: an instrument that records seismic waves
- seismology: the study of earthquakes
- shadow zone: area where no direct seismic waves can be detected
- sunquakes: caused by solar flares; much stronger than our earthquakes
- surface waves: seismic waves that travel along the Earth's surface
- surface waves: move ground up and down in circles; slowest; most destructive; feels like a roller coaster
- time-distance graph: compares the distance between P waves and S waves
- transform boundaries: moderate and shallow earthquakes occur here