5 Anatomy of an Earthquake Focus - where the first movement occurs in the earth’s crust.Epicenter - point on the earth’s surface where the earthquake is felt first.
6 Seismic Waves Body waves - travel thru the earth’s interior. Includes: P waves - primaryFastest waves, first to be detected.Move back and forth parallel to the motion of the wave.Move thru solids, liquids and gases.S waves - secondarySecond fastestMove perpendicular to motion of wave.Move only thru solids
7 Seismic Waves Surface waves - travel along the earth’s surface. Slowest moving wavesMove rock side to side and up and downCause the most damage during earthquakes
10 Seismology Seismology is the study of earthquakes. Seismograph - instrument that records seismic waves.
11 Earthquake Scales Mercalli Scale Richter Scale a seismic scale used for measuring the intensity of an earthquake. It measures the effects of an earthquake, and is distinct from the moment magnitude usually reported for an earthquake (sometimes misreported as the Richter magnitude), which is a measure of the energy releaseda numerical scale for expressing the magnitude of an earthquake on the basis of seismograph oscillations.
12 Measuring Earthquakes Magnitude - strength of an earthquake.Richter scaleIntensity - how much damage an earthquake causes.Mercalli scale