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Locating an Earthquake. Learning Goal. Analyze seismic data to predict the location and magnitude of an earthquake. Types of Waves. Primary Waves – (P-Wave) Fastest wave and moves rock particles back and forth. Secondary Wave – (S-Wave) Slower and moves rock particles up and down.
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Learning Goal • Analyze seismic data to predict the location and magnitude of an earthquake.
Types of Waves • Primary Waves – (P-Wave) Fastest wave and moves rock particles back and forth. • Secondary Wave – (S-Wave) Slower and moves rock particles up and down
Determining Distance • By comparing the time difference between S and P waves we can calculate the distance an earthquake is from a seismograph station.
Calculating Distance • P waves travel between 6 and 13 km/sec. S-waves are slower and travel between 3.5 and 7.5 km/sec. In most regions, study of numerous earthquakes with well-known epicenter locations results in an empirical S-P curve, such as the one shown to the right.
Magnitude • The magnitude of an earthquake provides a convenient measure of its size scaled to a small number usually less than 9. It is a unitless number, derived from the amplitude of ground motion associated with S-waves, adjusted for the distance between the epicenter and the seismograph station
Directions • Go to the following web site: http://www.sciencecourseware.com/virtualearthquake/vquakeexecute.html • Read through the Descriptions and directions. • Pick an earthquake to predict its location and magnitude. • Send your completion certificate to Jeff_Pierce@allenisd.org