USING GOOGLE EARTH FOR INQUIRY-BASED EXPLORATIONS OF PLATE TECTONICS

Instructor-compiled Google Earth (GE) kmz files provide an easy-to-use, powerful and customizable platform from which to explore plate tectonics. GE layers available from a variety of sources include seafloor age, 20 years of large earthquakes, magnitudes and depths of the last 7 days of earthquakes, volcanoes, “hot spot” track data, short-term and long-term average motion vectors, and commonly accepted plate boundaries. These layers can be variously compiled and activities targeted at a variety of student levels and inquiry levels. Several activities by the author are currently part of the SERC Cutting Edge resource collection (http://serc.carleton.edu/NAGTWorkshops/about.html).

At the introductory level, students can use GE to examine major features of the continents and seafloor and then follow a guided exploration of instructor-compiled layers relevant to plate tectonics. As an inquiry-based activity, students can be asked to define their own plate boundaries and describe plate boundary characteristics using GE data - and then compare their results with plate boundary models. Students can also derive plate motions from the seafloor age or oceanic “hot spot” layers. Students thus learn the basics of plate tectonics as well as the complexities; plate boundaries are not infinitely thin as depicted in textbook figures, for example.

At a more advanced level, students can form hypotheses about motions expected across particular plate boundaries and then test those hypotheses by comparing long-term average plate motions (derived from sea-floor age and hot-spot track data) to near-real time motions (from high-precision GPS data). Students find that plate tectonic theory is indeed supported by these two independent lines of evidence, but also discover sophisticated detail: plate motions change over time, some plate boundaries are quite diffuse while others are sharp, and internal plate deformation does occur.

This work was inspired by and builds upon the GIS-based Saquaro exercises by Michelle K. Hall (http://www.scieds.com/) but avoids the cost issues and steep learning curve associated with ArcGIS. Student evaluations of activities demonstrate that they feel engaged and empowered as they work with authentic data, and gain a sophisticated understanding of a fundamental theory as well as the process of doing science.