USING TIME-LAPSE VIDEO TO TEACH ABOUT SLOW GEOLOGIC PROCESSES

[This is Table 2 at the Digital Geology Express session—a blend of workshop and digital poster. Free participant sign-up at www.digitalplanet.org. Participants sit at tables and get hands-on interaction.]

We would like to demonstrate and discuss the use of relatively low-cost, computer-based digital imagery to create time-lapse videos of geomorphic processes in order to help students grasp the significance of the rates, styles, and temporal dependence of geologic phenomena. Our experience indicates that such videos help students to understand the relationship between gradual processes and landform development. Many geologic processes are slow and hence difficult for students to grasp. The advent of inexpensive web-cams and computers provides a new means to explore the temporal dimension of earth surface processes. To test the use of time-lapse videos in geoscience education, we developed time-lapse movies that record the evolution of two landforms: a stream-table delta and a large, natural, active landslide. The former involves well-known processes in a controlled, repeatable laboratory experiment, whereas the latter tracks the developing dynamics of an otherwise poorly understood slope failure. The stream-table delta is small and grows in about 2 days; we capture a frame on an overhead web-cam every minute. Before seeing the video, students are asked to hypothesize how the delta will grow through time. Students can then create the time-lapse videos on demand: specify start and stop times, and video duration. These elegantly show channel migration, progradation rates, and formation of major geomorphic elements (topset, foreset, bottomset beds). Post-lab tests and interviews with students indicate that these time-lapse videos significantly improve student interest in the material, and comprehension of the processes. In contrast, the natural landslide is relatively unconstrained, and its processes of movement, both gradual and catastrophic, are essentially impossible to observe directly without the aid of time-lapse imagery. We constructed a remote digital camera which captures 1 photos/hour of the toe. The toe is extremely active geomorphically, and the time-lapse movie helps us (and the students) constrain the style, frequency, and rates of movement, surface slumping, and debris-flow generation.