Volcanism and Tectonics: An exploration of volcanoes and volcanic deposits using Google Earth

B. Surpless, Trinity University, San Antonio, Texas

Summary

This is a stand-alone exercise that serves as a culmination activity to bring together student knowledge of volcanic rocks (compositions, textures, and types), volcanic landforms, volcanic hazards, and plate tectonics.

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Learning Goals

  • Volcanic landform analysis
  • Map interpretation
  • Volcanic hazard analysis
  • Accurate hand sample description and interpretation
  • Slope measurement
  • Oceanic hot spot eruptive products and landforms
  • Oceanic-continental eruptive products and landforms
  • Analysis of topographic and atmospheric controls on volcanic deposits
  • Age pattern analysis
  • Interpretation of rock color relative to atmospheric exposure time
  • Synthesis of ideas involving magma composition, plate tectonic setting, and relative volcanic hazard

Context for Use

This is an activity designed for an introductory level physical geology lab course, but the activity could easily be modified to be completed by students outside of class or lab time. The rigor of this activity could be beefed up for an upper level course, or it could be modified for much younger students (a modified version has been used to teach 8-year-olds about volcanoes).

Description and Teaching Materials

Google Earth .kmz file ( 3.6MB Mar2 10)

Teaching Notes and Tips

Skills needed by students prior to this activity (as submitted):
  • basic mineral identification
  • basic volcanic rock identification
  • compositional terminology (i.e., felsic vs. mafic)
  • textural terminology for igneous rocks
  • basics of plate tectonics and hot spots
  • basics of the initial generation of magmas
  • ways that magmas can be modified prior to eruption

The set-up should take less than 30 minutes. The computer set-up is probably the most time-consuming task (1 computer / 2 students; network access; .kmz file available).

Google Earth Instructor Notes (Acrobat (PDF) 1.8MB Mar2 10)

Assessment

The instructor uses student answers to questions from Parts I. and II. to determine whether students have a solid understanding of the different concepts introduced throughout the activity. This will obviously depend heavily on where the activity is situated in the course, the level of the course, and the student population (science vs. non-science majors, etc.). In Part III., students are required to draw on their previous knowledge as well as the investigation and analysis performed during the activity to summarize the tectonic and magmatic processes that led to what they observed. Good student responses will make the connections between tectonic setting, erupted magma composition, and relative volcanic hazard when answering these final questions.

References and Resources

  • Luedke, R.G., and Smith, R.L., 1982, Map showing distribution, composition, and age of Late Cenozoic volcanic centers in Oregon and Washington: Miscellaneous Investigations Series, Map I-1091-D.
  • Luedke, R.G., and Smith, R.L., 1988, Map showing distribution, composition, and age of late Cenozoic volcanic centers in Hawaii: U.S. Geological Survey Miscellaneous Investigations Series, Map I-1901-G, scale 1:100,000.
  • Topinka, L., 2007, Mount St. Helens, Washington, May 18, 1980 Blowdown, accessed February 25, 2010.
  • Topinka, L., 2008, Mount St. Helens, Washington, Crater and Dome Images 1980-2004, accessed February 25, 2010.