Exploring Tectonic Motions with GPS

Shelley Olds, UNAVCO
Jennifer Pickering, Alaska Pacific University and Anchorage School District
Beth Pratt-Sitaula, UNAVCO

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Summary

Learners study plate tectonic motions by analyzing Global Positioning System (GPS) data, represented as vectors on a map. The activity is designed to use the online map tool GPS Velocity Viewer (opens in a new window), but instructors can instead print the provided hard-copy maps for Alaska or Western United States. By observing changes in vector lengths and directions, learners interpret whether regions are compressing, extending, or sliding past each other. To synthesize their findings, learners identify locations most likely to have earthquakes, and defend their choices by providing evidence based on the tectonic motions from the GPS vector and seismic hazards maps.

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Context

Audience

This activity was developed for middle school and high school students, grades 6 - 12. However, its focus on data makes it adaptable for introductory college courses.

Skills and concepts that students must have mastered

Students should be able to read maps and understand map scale. Familiarity with vectors is also recommended.

How the activity is situated in the course

This activity can be used at any time in an earth science class particularly within a sequence of lessons about plate tectonics. It can be used as an introductory activity for students to explore current plate motions and to learn about compression, extension, and horizontal slip. The activity takes about one hour of class time.

Goals

Content/concepts goals for this activity

Learners will be able to:

  • Analyze and describe regional plate motion data as represented as vectors
  • Interpret crustal deformation based on velocity vector map
  • Correlate GPS vector gradients on a map with plate tectonic boundary types
  • Make a claim based on evidence about which locations are most likely to have earthquakes

Higher order thinking skills goals for this activity

  • Making claims based on evidence

Other skills goals for this activity

  • Using maps
  • Using online data portals

Description and Teaching Materials

Activity

See attached file for instructor notes, NGSS alignment, student exercise, and links to supporting resources.
Exploring Tectonic Motions with GPS Activity (Acrobat (PDF) 5MB Feb11 22)


Supporting Presentation/Audiovisual

Student handout answer key

Editable files

Teaching Notes and Tips

For instructors who need a little more background on GPS, plate tectonics, and reference frames, here are some resources that could be reviewed. More options are below in References.

  • NASA: How Does GPS Work?
  • NASA: How Does GPS Get You a Pizza?
  • Measuring Plate Tectonic Motions with GPS (Opens in a new window)- this animation introduces reference frames
  • GPS Velocities & Reference Frames
  • For support using the GPS Velocity Viewer online tool, see this User Guide GPS Velocity Viewer Guide Alaska (Acrobat (PDF) 1.6MB Jan20 22) or the instructional video provided on the website, just above the map.
  • Particularly if you have younger learners, it might help to demonstrate the measuring of one of the vectors and converting that to mm/yr of real motion in that spot.
  • A possible extension would be to visit a nearby Network of the Americas (NOTA) GPS station. Check the NOTA website for the location map. There are over 1100 stations! One might be near you.
    Note: when installed, most of these stations were part of different GPS networks that have since been combined into NOTA. For instance you might still see references to the earlier Plate Boundary Observatory (PBO) network, which was just in the USA.

Assessment

Formative assessment of student understanding can be gathered from classroom observation and discussions with individuals or small groups.

The student exercise serves as the summative assessment for the activity. Some questions have clearly correct answers. For open-ended questions, students can be assessed based on a simple 2-point scale.

  • 2 points = correct answer with thorough supporting evidence and/or complete description
  • 1 point = answer not completely correct or lacking thorough supporting evidence or description
  • 0 points = incorrect answer

References and Resources