Segment Two: When the Earth Shakes
This video segment explains what happens when movement occurs along the crustal breaks, known as faults. The video begins with a re–creation of the 1959 earthquake in Montana’s Hebgen Valley, examining the geologic structure responsible for the quake and the resulting surface features. Students also learn about seismic waves. During a visit to the seismic station at the University of North Carolina at Chapel Hill, students see how a seismograph works, visit a working seismic vault and learn how seismic waves are measured. Students also watch scientists interpret seismograms and locate the epicenter of an earthquake. The video also explores “ring-of-fire” seismic belts and the Alaskan earthquake of 1964. This video segment ends by suggesting that future research may enable scientists to predict earthquakes, thus helping to reduce property damage and loss of life.