Measuring Ground Motion with GPS: How GPS Works
With printouts of typical GPS velocity vectors found near different tectonic boundaries and models of a GPS station, demonstrate how GPS work to measure ground motion.
GPS velocity vectors point in the direction that a GPS station moves as the ground it is anchored to moves. The length of a velocity vector corresponds to the rate of motion. GPS velocity vectors thus provide useful information for how Earth's crust deforms in different tectonic settings.
Skills and concepts that students must have mastered
Learners should have a general understanding of GPS. Learners should also have some familiarity with the concept of plate tectonics.
How the activity is situated in the course
This demonstration is particularly useful when discussing plate tectonics, plate boundary types, and the use of GPS to measure ground motion. This demonstration is expected to take 5 - 15 minutes.
Content/concepts goals for this activity
Earth's surface is constantly in motion.
- GPS can be visualized as velocity vectors.
- A velocity vector points in the direction that a GPS station is moving and its length is proportional to the rate of motion.
- Velocity vectors from GPS data show how Earth's crust moves in different tectonic settings.
Higher order thinking skills goals for this activity
- Discuss relative movement of tectonic plates such as the Pacific and North American plates in California, using GPS data
Other skills goals for this activity
Description and Teaching Materials
Supplementary Materials: Map Examples (Zip Archive 17.7MB Nov12 21)
Supplementary Materials: Tectonic Setting Maps and Scenarios (Zip Archive 286kB Nov12 21)
Measuring Ground Motion with GPS Writeup (Acrobat (PDF) 50kB Nov12 21)
Teaching Notes and Tips
A complete run through of the demonstration can be found on the UNAVCO YouTube Channel.
- 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