RHNC+2.2

toc 2.2 Measuring Earthquakes

Vocabulary

 * focus** - where rocks beneath surface breaks;triggers earthquakes
 * epicenter** - surface directly above focus
 * seismic waves** - vibrations from earthquake
 * p waves** - earthquake waves that act like accordian
 * s waves** - earthquake waves that vibrates side to side and up and down
 * surface waves** - slower than p and s waves, more severe ground movements
 * magnitude** - measurement of earthquake waves
 * Mercalli scale** - measurement of earthquake waves
 * Richter scale** - rates size of seismic waves
 * moment magnitude scale** - estimates total energy from earthquake

Seismic Waves

 * primary waves
 * "P" waves
 * first to arrive
 * Secondary waves
 * "S" waves
 * after p waves
 * Surface waves
 * more powerful than p and s waves

Detecting Seismic Waves

 * electronic seismographs

Measuring Earthquakes

 * Magnitude
 * Mercalli scale
 * Richter Scale
 * Moment magnitude scale

Locating the Epicenter

 * seismic waves
 * p and s waves