Earthquake 3
posted February 15, 2000 as a Math Forum EPoW

Introduction: In the Earthquake problem series, students play the role of a scientist trying to determine the location of the epicenter of an earthquake.

Where’s the Math: In this problem, students use their skills at interpreting graphs and manipulating rate/time equations in an applied situation, namely, interpreting the difference in arrival times of the two waves at a scientist's seismograph. Standards: Algebra, measurement Role of Components: The Earthquake problem series uses World to animate the motion of characters against the background image. Graph works with simple function to plot distance over time, which is controlled with simple clock and monitored with time label. Instructions are displayed and solutions are entered in a text entry box.

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Sample submitted solution:

From: Hana, Lisa, age 13
School: Issaquah Middle School, Issaquah, Washington

1. The time difference measured between P & S waves for an earthquake was 10 seconds. Use the graph to find how far the epicenter was from the seismograph.
According to the graph the epicenter would be 5 miles away from the seismograph to get those results.

2. Using the distance found in question 1, which of the following are possible locations for the epicenter: Town Dump, Highway, River Bend, City Hall, School, and/or the Park? (Hint: You can drag the epicenter around to find the place or places where the distance matches the answer for question 1.)
One possibility is the town dump because it's 5 miles away from the seismograph. The school and the highway are also other possibilities. All of the other landmarks aren't possible because they are either too close or too far away.

3. Describe as carefully as you can all the possible locations of the earthquake.
Everything along the five mile radius of the seismograph could be a possible location for the epicenter.

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