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Show • Will I be swallowed alive during an earthquake? The ground docs not open up and swallow you (this is a myth believed by many adults and children). The ground may crack open during an earthquake, but you will not be swallowed alive. • What is a seismometer, seismograph, and a seismogram? A seismometer is the instrument placed in the ground to detect vibrations of the earth. A seismograph is the machine that records these vibrations. A seismogram is the hard copy (usually paper or film) record of the earth's vibrations as recorded by the seismograph. • When were the largest earthquakes in Utah? Historically [since time of settlement (1850)]: 1934 Hansel Valley earthquake, magnitude 6.6, and the 1901 Richfield earthquake, magnitude 6 1/l.. • What is an earthqu ake swarm? A series of earthquakes with no distinct main shock. • What is t•he Richter Scale? A scale for determining the size of an earthquake from the trace of the vibration registered on a seismograph instrument The maximum amplitude of the vibration is adjusted for the distance of the earthquake center from the instrument This is not a physical scale (in other words, one cannot look at or hold the "Richter Scale"). There is no upper or lower bound to the scale. Each 1-unit increase in the Richter Scale, roughly corresponds to a 30-fold increase in energy release. The Richter magnitude is the figure generally reported in the press. The Richter magnitude value is the same at all locations. • Can we predict earthqu akes? No. We cannot predict earthquakes in the U.S. (except at Parkfield, CA). In order to predict earthquakes you need a long time-line. The U.S. has been settled for about 200 years (139 years in Utah). When you have earthquakes that occur every 5001000 years, it is difficult to draw conclusions about average repeat times since we don't know when the last one was. In China, they have 5000 years of history from which to draw conclusions, allowing the Chinese to predict earthquakes more reliably. The Chinese also have a political structure that allows them to easily evacuate entire cities. In the U.S., such an evacuation procedure would be difficult. The Chinese have correctly predicted earthquakes, evacuated cities and saved lives, have had earthquakes occur with no predictions, and have predicted earthquakes that have never occurred. |
