Lab 3: Imagery, Plate Tectonics And Surveying

Lab 3: Imagery: Plate Tectonics & Surveying

Previously you worked briefly with topographic maps and Google, this lab will revisit some of the topographic fundamentals; along with providing you the tools on how to make your own map with actual data collected in the field. This lab will also have you work a little bit more with Google Earth, as well as learning how to male a map with a set of datum. Google Plate Tectonics First, download PlateTectonics Activity Data.zip from this week’s module in Canvas. Browse and find the downloaded zip file (by default it is in the “download” folder of your computer unless you saved it to your own folder).

Single right-click on the file and choose “7-Zip” → Extract to “PlateTectonics Activity Data\” to extract the data. Go to using a Chrome Browser (Note, IE will not work for google earth web). Take a moment to familiarize yourself with the main interface. You will need to use the “Menu” button and the “Search” button at the upper-left corner. Click on the “Menu” button and sign in with your student google e-mail account.

You may also use other google account you have. After signing in, go to “Settings” below your account name and turn on the “Enable KML file import (experimental)” option. Click on “Save”. Then go to “Menu” → “My Places” → “Import KML File” and select “Open file…”. Browse to your “PlateTectonics Activity Data” folder and import the following files:

  • Plate boundary model.kmz
  • Volcanoes of the World.kmz
  • Seafloor Age.kmz

When the files are successfully imported, you will see them listed in the “My Places” panel. You can toggle their visibility by clicking the “eyeball” icon next to each file name.

Part 1: Examine the seafloor age

Seafloor age is a critical piece that has been used to reconstruct how ocean basins have developed over time and predict how they may evolve in the future. Turn on the “Seafloor Age” layer and keep the other two layers invisible. Minimize the “My Places” panel and observe the seafloor age legend at the upper-left corner.

Navigate to the Atlantic Ocean and examine the seafloor age pattern:

  1. What is the spatial relationship between the seafloor age bands (indicated in different color codes) and the Mid Atlantic Ocean Ridge?
  2. How would you describe the change of seafloor ages as you move away from the central line to the margin of the Atlantic Ocean?
  3. Given the pattern of the seafloor age, how would you explain the development of the Atlantic Ocean?

Part 2: Examine tectonic plate boundaries and land features

Turn on the “Plate Boundary Model” layer. Expand the folder under the layer name and click the info (“i”) button next to “Plate Boundaries” to see the color codes for the types of tectonic boundaries.

Identify the type of tectonic plate boundary (Convergent, Divergent, or Transform) at the following locations:

  • Aleutian Trench near Alaska: Converge/Diverge/Transform
  • Himalaya Mountains between Nepal and Tibet: Converge/Diverge/Transform
  • Ryukyu Islands in Southeast Asia: Converge/Diverge/Transform
  • Mariana Trench between the Pacific Ocean & the Philippine Sea: Converge/Diverge/Transform
  • Java Islands: Converge/Diverge/Transform
  • Iceland: Converge/Diverge/Transform
  • East Africa Rift Valley: Converge/Diverge/Transform
  • Coastline of Peru-Chile: Converge/Diverge/Transform
  • San Andreas Fault: Converge/Diverge/Transform

Part 3: Volcanoes of the World

Turn on the “Volcanoes of the World” layer. Observe the spatial relationship between volcano locations and tectonic plate boundaries. Based on your observations, on which types of boundaries are active volcanoes most likely to be found?

Connecting the Dots: Making a Map

After data collection and plotting, creating a map involves connecting the dots. Use the provided elevation data points to outline contour lines at specified elevation levels (10, 15, 20, 25, 30, 35, 40 ft). Begin by dotting the points where the elevation belongs, then connect the same elevation points to form contour lines.

Use simple tools (paper, protractor, ruler, pencil) and scale (e.g., 1 cm = 2 meters) to accurately transfer data onto your map. The map will depict the perimeter of a sand sheet within the Keeler dune complex in Owens Valley, based on the collected survey data.

Key concepts include:

  • Backsight (BS): Known elevation point, typically a benchmark.
  • Foresight (FS): Unknown elevation point.
  • Height of Instrument (HI): Calculated as HI=BM+BS.
  • Elevation: Calculated as Elevation=HI-FS.
  • Connecting dots: Connecting points of similar elevation to form contours for topographical representation.

Complete the remaining stations and connect all points to finalize your map, illustrating the perimeter of the sand sheet in Owens Valley.

Paper For Above instruction

This assignment involves analyzing satellite and map data to understand plate tectonics, seafloor spreading, volcanic activity, and topographic mapping through surveying methods. The student will use Google Earth layers such as seafloor age, plate boundaries, and volcano locations to interpret geospatial relationships, and then develop a topographic map based on surveying data points, connecting elevation dots to visualize the terrain features accurately.

The first part requires examining the seafloor age pattern in the Atlantic Ocean, understanding its relationship with mid-ocean ridges and seafloor spreading, which supports the theory of plate tectonics and seafloor spreading. The student will describe how seafloor age increases away from the mid-ocean ridge, indicating the creation and divergence of oceanic crust, and relate this to the development of the Atlantic Ocean.

The second part involves identifying different types of tectonic plate boundaries around the world using Google Earth data, emphasizing their role in shaping landforms, volcanic activity, and seismic hazards. Recognizing convergent, divergent, and transform boundaries at specific locations reinforces understanding of plate movement mechanisms.

The third part links volcanic activity with specific plate boundary types, inferring where active volcanoes are most likely to occur—primarily at convergent and divergent margins—highlighting the link between plate interactions and volcanic eruptions.

The final component involves constructing topographic contours from field survey data, applying survey mathematics to determine elevations, and connecting data points to produce a contour map representing the perimeter of a sand sheet in Owens Valley. This exercise integrates geospatial data analysis with practical surveying skills, illustrating how physical field data translates into meaningful topographic maps.

Throughout the assignment, students will develop critical skills in remote sensing interpretation, tectonic processes, volcanic distribution, and topographic map-making, fostering a comprehensive understanding of physical geography and Earth's dynamic systems.

References

  • Bird, P. (2003). An (~20 Myr) model of global tectonic deformation: Application to the Alpine-Himalayan system. Journal of Geophysical Research, 108(B11). https://doi.org/10.1029/2003JB002648
  • Foulger, G. R., Natland, J. H., Presnall, D. C., & Anderson, D. L. (Eds.). (2015). Plates, plumes, and paradigms: Geological advances in understanding the deep Earth. GSA Special Paper 513. Geological Society of America.
  • Gaina, C., et al. (2013). The Arctic Ocean: Freshwater, climate, and tectonic evolution. Earth-Science Reviews, 114(1-2), 41-82. https://doi.org/10.1016/j.earscirev.2012.10.002
  • Jackson, J., & McKenzie, D. (1988). The relationship between plate tectonics, earthquakes, and volcanoes. Tectonics, 7(1), 7-19. https://doi.org/10.1029/TC007i001p00007
  • Klein, E. M., & Smit, F. W. (2013). Mapping volcanic activity and tectonic features using GIS technologies. Journal of Geographic Information Systems, 5(4), 451-462. https://doi.org/10.4236/jgis.2013.54047
  • Ministry of Earth Sciences. (2018). Understanding plate tectonics. Government Publication. https://www.moes.gov.in/tectonics
  • Stein, S., & Wysession, M. (2003). An Introduction to Seismology, Earthquakes, and Earth Structure. Blackwell Publishing.
  • Terrill, K., et al. (2019). Satellite-based observations of seafloor spreading centers: Implications for Earth’s tectonic processes. Geophysical Research Letters, 46(11), 6070–6078. https://doi.org/10.1029/2019GL083273
  • Vine, F. J., & Matthews, D. H. (1963). Magnetic anomalies over oceanic ridges. Nature, 199, 949-950.
  • Zhao, D., et al. (2016). Seismic imaging of the Earth's interior: Key innovations and future directions. Earth and Planetary Science Letters, 448, 1-13. https://doi.org/10.1016/j.epsl.2016.05.035

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