Exploring Tectonic Motions of Alaska & Western United States

Shelley Olds, UNAVCO
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This activity was selected for the On the Cutting Edge Reviewed Teaching Collection

This activity has received positive reviews in a peer review process involving five review categories. The five categories included in the process are

  • Scientific Accuracy
  • Alignment of Learning Goals, Activities, and Assessments
  • Pedagogic Effectiveness
  • Robustness (usability and dependability of all components)
  • Completeness of the ActivitySheet web page

For more information about the peer review process itself, please see https://serc.carleton.edu/teachearth/activity_review.html.

This page first made public: May 26, 2018


Students analyze data from GPS data represented as vectors on a map of Alaska or western United States to study tectonic motions at plate boundaries and within the North American and Pacific tectonic plates. Students discover whether motion is compressing, extending, or sliding the land within each region of the plate. By observing the vector lengths and directions, students interpret the motion within Alaska or several regions of Western USA (Pacific Northwest, Basin & Range, and California). To synthesize their findings, students identify two locations most likely to have earthquakes. Students need to be able to defend their choices by providing evidence based on the tectonic motions from the map/poster and seismic hazards.

Disciplinary Core Ideas

History of Earth: HS-ESS1-5
Earth' Systems: MS-ESS2-2
Earth and Human Activity: MS-ESS3-2, HS-ESS3-1
Science and Engineering Practices
4. Analyzing and Interpreting Data
5. Using Mathematics and Computational Thinking
6. Constructing Explanations and Designing Solutions
Crosscutting Concepts
4. Systems and System Models
7. Stability and Change



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.

How the activity is situated in the course

This activity can be used at any time in an earth science class particularly with in 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.


Content/concepts goals for this activity

Learners will be able to:

  • Describe how velocity vectors from GPS stations inform us about tectonic motion and plate boundaries.
  • Describe and draw a velocity vector
  • Analyze and describe regional plate motion data as represented as vectors.
  • Interpret crustal deformation based on velocity vector map.
  • Identify, discuss and defend the locations they chose that are most likely to have earthquakes.

Higher order thinking skills goals for this activity

Not applicable

Other skills goals for this activity

Using maps

Description and Teaching Materials

Using a map showing the horizontal velocities of GPS stations in the Plate Boundary Observatory and other GPS networks in Alaska and Western United States, students are able to describe the motions in different regions by interpreting the vectors resulting from long-term high-precision Global Positioning System (GPS) data.

Instructor should print out copies of the Tectonic Motions poster/s that they intend to have students use: Alaska and/or Western USA. 8.5x11" versions are included in the zipped file below. Full size versions can be downloaded from UNAVCO's Tectonic Motions Posters webpage or requested from UNAVCO.

These zipped files include student exercises in docx and pdf, tectonic motions posters at 8.5x11", and seismic hazard maps for each region.

Teaching Notes and Tips

  • Optionally, students can begin the activity by learning about geodesy and GPS and study a physical demonstration to understand the architecture of GPS, from satellites to sensitive stations on the ground (see animations and videos below in the References and Resources section).
  • A possible extension would be to visit a nearby Plate Boundary Observatory (PBO) GPS station. Check the PBO website for the location map. There are over 1100 stations! One might be near your school.


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 description1 point = answer not completely correct or lacking thorough supporting evidence or description0 points = incorrect answer

References and Resources

  • GPS Velocity Viewer allows viewers to explore GPS motions around the world
  • How GPS Works
  • The activity was presented as part of the EarthScope ANGLE Educator Workshops.
  • Send questions or comments about this activity to education –at- UNAVCO.org