Emergent Models for Teaching Geology and Geophysics Using Google Earth

A significant limitation of Google Earth is that, whereas maps draped over the terrain may be made semi- transparent, the terrain itself is always opaque. It is not possible to see into the earth's interior - a region of particular interest to geologists and geophysicists. Furthermore, learning difficulties undoubtedly result for students because internal features of the Earth are not visible to them. At Fall AGU 2007, we showed how blocks of the earth's sub-surface could be made to emerge from the Google Earth terrain model so as to reveal crustal cross sections using either hand-drawn sketches or real data from geoseismic transects. We have refined these models to include surface topography on the tops of blocks and have produced a set of emergent cross sections representing various tectonic settings, including divergent and convergent margins, deep mantle plumes, and paleo-tectonic reconstructions. Comparing our models with typical sketches from textbooks reveals large disparities between cartoon representations of plate tectonics and real geometries from present plate configurations. Key discrepancies include substantial vertical exaggeration in cartoon models and mostly non-orthogonal collisional plate boundaries in the real world. These differences likely hinder understanding and lead to persistent misconceptions for students. With the support of the NSF CCLI program, we plan to recruit a cohort of instructors at 2- and 4-year colleges to participate in workshops in which sub-surface sketchup models will be generated in hands-on demonstrations. Participants will test the effectiveness of emergent models as learning objects in real classroom settings and compare the relative merits of Google Earth illustrations based on spatially-accurate research data versus cartoon representations of geological structures.