Where was that earthquake?

Sara Harris, Brett Gilley, and Ido Roll
University of British Columbia
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Initial Publication Date: December 12, 2013 | Reviewed: July 21, 2015
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Undergraduate introductory-level geosciences lab for majors and non-majors.

Skills and concepts that students must have mastered:

No prior experience needed.

How the activity is situated in the course:

This is part of a sequence of lab activities related to earthquakes.

National or State Education Standards addressed by this activity?:


Content/concepts goals for this activity:

By the end of this activity, students will be able to:
  1. Explain how differences in travel times can be used to estimate distance traveled
  2. Locate a starting point on a map using paired arrival time data.

Higher order thinking skills goals for this activity:

Other skills goals for this activity:

Description of the activity/assignment

In small groups, students "invent" a way to figure out the location of a house, based on the walking times of two housemates to various locations near their house. This cover story is an analogy for using the arrival time differences between P and S waves to locate an earthquake epicenter. Students then create and compare graphs analogous to a Jeffreys-Bullen diagram and come up with a generalized way to use this type of graph to find distances. The activity prepares students for learning how to locate an epicenter and makes the relationship between distance and arrival times meaningful, since they have to figure out how to use arrival time differences to estimate distance.

Determining whether students have met the goals

  1. Give students another location in the same scenario, a different distance away.
  2. Change Polly and/or Sam's speeds and apply to the same scenario.
  3. Give students some data for another of the pairs of friends and ask them to locate this different house on the same map.

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