Earthquake Epicenter Location Exercise using Google Earth and OneNote

Jeffrey A. Nunn
Department of Geology and Geophysics, Louisiana State University
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Students are provided with data from 4 seismograms which are used to plot the epicenter of an earthquake using OneNote to pick the P-S wave arrival gap and Google Earth to plot the circles which intersect at the epicenter.

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Introductory physical geology course for majors and non-majors.
Integrates geophysics into a core course in geology
Designed for an introductory geology course

Skills and concepts that students must have mastered

P-wave and S-wave propagation including type of motion, velocity, and amplitude. Identifying P-waves and S-waves on a seismogram.

How the activity is situated in the course

This is a stand alone laboratory exercise in our physical geology laboratory course


Content/concepts goals for this activity

Interpret a seismogram for P-wave and S-wave arrivals. Calculate the distance from the earthquake based on the time lag between P-wave and S-wave arrival, determine earthquake location by using 3 or more intersection circles

Higher order thinking skills goals for this activity

This exercise allows students to interpret real data and demonstrate for themselves that this method for epicenter location works and why it works. Sharing data in class also allows them to see how errors enter into scientific calculations. Some students do a poor job of picking the arrivals so the intersection of circles is poor.

Other skills goals for this activity

Searching the WWW and working in groups

Description of the activity/assignment

Students in groups of two are giving access to 3 component seismograms from four locations through Google Earth. They are then asked to pick the P-wave and S-wave arrivals using OneNote and convert the time lag into a distance to epicenter. A circle drawing application in Google Earth then allows them to plot possible locations for the earthquake epicenter. This activity gives students practice in interpreting data, analyzing uncertainty and error in data or data analysis, and peer teaching Uses online and/or real-time data

Determining whether students have met the goals

Students turn in a digital report showing their picks for P-wave and S-wave arrivals, calculations of distance, and Google Earth map with intersection circles showing location of the epicenter. Students also take a short pre- and post-test to see if they have learned basic concepts about the relative velocity and type of motion of seismic waves and how it can be used to locate the epicenter.

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