“The Video Helps”: Examples of animations that illustrate ground-penetrating radar wave behavior.

Abstract:

Teaching geophysics requires one to conceptualize two-- and three-dimensional physical phenomena and changes through time. Ground-penetrating radar (GPR), for example, is an electromagnetic wave that travels out from a transmitter and reflects off buried features. Changes in amplitude and phase over time are essential concepts to understand, yet a single image can not adequately represent them. A sequence of images, which can easily be converted to animation, is a better approach. We present a small collection of GPR propagation videos meant to enhance the learning experience. The first set of videos is part of a geophysics learning module hosted on SERC that introduces students to the application of GPR to detect anthropogenic targets (i.e., pipes). One can follow the electromagnetic wave travel out from a source, attenuate as a function of distance from the source and ground material, and reflect at the boundary between ground material and buried targets. The second set of videos is outreach material for NASA’s TubeX project, which investigates the GPR response of air-filled lava tubes. Here videos similar to the first set are integrated with terrestrial LiDAR point cloud fly-throughs through video editing software. The results are eye-catching animations that illustrate wave behavior and provide a sense of scale and real-life placement.