Mapping Plate Tectonic Boundaries

Nathan Toke, Utah Valley University
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Initial Publication Date: September 9, 2019 | Reviewed: December 10, 2020

Summary

In this classroom activity, students will work in groups to observe how patterns of topography, bathymetry, earthquake locations and depths, and the location of volcanoes vary across regions of the Earth. They will then use this data to predict and map the locations and types of major plate tectonic boundaries. Finally, they should begin to form an intuition about the 3D nature of these plate tectonic boundaries by sketching a cross sectional concept diagram through a convergent boundary, plotting surface topography, earthquakes' locations below the surface, the position of volcanoes at the surface, and inferring the location of the plate tectonic boundary at depth.

Used this activity? Share your experiences and modifications

Context

Audience

This activity is suitable for at least three audiences: 1) as a review of plate tectonics for the beginning of an upper division course in geology (to get students refreshed that have already had one or two courses on the subject) OR 2) as an activity to accompany readings/lecture material on plate tectonics in a college-level introduction to geology class. OR 3) This material can also be made suitable for pre-college students by modifying the assessment questions to suit the audience.

Skills and concepts that students must have mastered

Students must understand at a basic level what the following geologic phenomena are:
earthquakes, volcanoes, topography.
Students must have a basic understanding of how to read maps and interpret color scales and other map symbology.

How the activity is situated in the course

It is recommended that this activity be completed in groups of 2-4 students. It can be done as part of a lab or in a lecture-based class. It will require at least 40 minutes to complete. For some students this will be too rushed. The time to completion will vary depending on the depth of questioning and assessment required by the instructor. The questions that I have provided here are a guide and should be modified to fit your particular goals and time constraints.

This activity can be done on paper maps or with digital annotation on the accompanying PDF map files, but that requires a lot of expensive printing or a very well-equipped technology classroom. I prefer to create multiple sets of laminated large-format printed maps and then have the groups use those laminated maps to map the plate boundaries using dry erase markers that I can erase after the class is over and before the next class section uses them (don't wait too long, because even dry erase becomes difficult to erase after several weeks).

Goals

Content/concepts goals for this activity

Students will review the concept of plate tectonics in relationship to topography, volcanoes, and earthquakes.

Students should be able to identify convergent plate boundaries based upon the following evidence:
  1. Presence of deepening earthquakes inboard of the plate boundary.
  2. Presence of a volcanic arc, inboard of the plate boundary.
  3. Presence of an oceanic trench.
Students should be able to identify divergent plate boundaries based upon the following evidence:
  1. Presence of a mid ocean ridge.
  2. Presence of volcanoes within a rift.
  3. Presence of shallow earthquakes.
Students should be able to identify transform plate boundaries based upon the following evidence:
  1. Presence of offset mid-ocean ridges
  2. Presence of offset land masses (e.g., Haiti/Cuba)
  3. Presence of shallow earthquakes along a topographically defined lineament.
Students may also learn to identify hotspots based upon the following evidence:
  1. Volcanoes unassociated with plate boundary topography.
  2. A chain of seamounts in bathymetry

Higher order thinking skills goals for this activity

Students can also gain an intuition about the differences between continental and oceanic crust:
  1. The relative age of continental land masses and oceanic crust based upon the morphology of the land. i.e., Oceanic crust appears young because of its sharp undistorted tectonic margins. Continental crust appears much more random in topography because it's long history of many plate tectonic events.
  2. The presence of continental shelves as evidence of sea level change and as evidence for differences in crustal density.
  3. Students can analyze earthquake depths to describe the geometry of plate boundaries by plotting earthquake depths along a profile line crossing the different types of plate boundaries.

Other skills goals for this activity

  • Students will learn to interpret color hillshade maps of the Earth.
  • Students will gain experience utilizing map scale bars and legends.
  • Students will practice using data to make inferences.

Description and Teaching Materials

This is an activity designed for geology students of various experience to practice mapping plate tectonic boundaries using data on topography, earthquakes, and volcanoes.
Set of Maps of Regions of the Earth (Acrobat (PDF) 65.6MB Jul28 19)

Teaching Notes and Tips

Notes on Datasets:
The GIS data utilized when I created these maps (in 2011) include the following datasets:
Topography: NOAA ETOPO-1 Global Relief Map (1 km resolution) dataset with ice. https://www.ngdc.noaa.gov/mgg/global/global.html
Volcanoes: Locations of active volcanoes from the Smithsonian's Global Volcanism Program:
http://volcano.si.edu/list_volcano_holocene.cfm
Earthquakes: I downloaded the global record of earthquakes from before year 2000 that were greater than Magnitude 4.5 locations and depths information using the earthquake catalogue now located at: https://earthquake.usgs.gov/earthquakes/search/

Notes on the Worksheet Questions:
The included worksheet is only a guide. It is aligned with how I usually run this activity, but could easily be modified to shorten the activity or to make it more in-depth.

Other Notes:

  • Many more earthquakes have occurred since 2000 and could be added to the maps. Additionally, one could scale the earthquakes by magnitude, which I have not done here so that the topography would not become obscured. This map does not include earthquakes smaller than M4.5, if included (not available globally), it would be hard to read the map, but the plate boundaries that have only sparse earthquakes would show up better.
  • A common issue that the students and I run into with the volcano data is that it only includes eruptions that have either been witnessed or studied geologically, therefore most underwater volcanoes along the mid ocean ridges are not on the map.
  • The topography of Transform boundaries is hard to discern on the continents and easy to see in the Ocean basins.

Assessment

Assessment for this activity can be done in several ways. I like to do the following:
  1. Reserve enough time to project the included world topographic map on the white board of the classroom and let each group come to the front of the class and add 1-2 plate boundaries to the map and to explain to the class what data led them to that conclusion. This will undoubtedly lead us to realize that some groups made errors, or missed some boundaries, which creates good teaching moments.
  2. I will also collect the worksheets to check attendance and will generally grade the assignment, taking off only a few points for incomplete explanations and poorly formed ideas and then utilizing these misses as teaching points when reviewing for exams or moving back into lecture mode. E.g., reviewing common mistakes missed on the last activity.
  3. I also will check that each group mapped the plate boundaries and include that in their worksheet grade.

References and Resources

The GIS data utilized when I created these maps (in 2011) include the following datasets:
Topography: NOAA ETOPO-1 Global Relief Map (1 km resolution) dataset with ice. https://www.ngdc.noaa.gov/mgg/global/global.html
Volcanoes: Locations of active volcanoes from the Smithsonian's Global Volcanism Program:
http://volcano.si.edu/list_volcano_holocene.cfm
Earthquakes: I downloaded the global record of earthquakes from before year 2000 that were greater than Magnitude 4.5 locations and depths information using the earthquake catalogue now located at: https://earthquake.usgs.gov/earthquakes/search/