EVALUATION OF AERIAL REMOTE SENSING TECHNIQUES FOR DEFINING CRITICAL GEOLOGIC FEATURES PERTINENT TO TUNNEL LOCATION AND DESIGN

Operational testing and evaluation of commercially available remote sensing data including space imagery, side-looking airborne radar, black-and-white, color infrared, color, and low sun angle photography. Multispectral scanner data (including thermal infrared), and airborne geophysical systems over the East River Mountain tunnel in West Virginia and the Carlin Canyon tunnel in Nevada demonstrates that, if integrated with conventionally acquired geologic data, remote sensing can reduce the cost of tunnel site selection and evaluation and in almost every instance provides unique geologic information. There is no single array of remote sensors that is optimal for all tunnel sites, but there is a suite of remotely sensed data including space imagery, black-and-white and color aerial photography, low sun angle photography, and side-looking airborne radar (if it already exists) that should be analyzed for most sites because of high information content and relatively low cost. Several other systems including side-looking airborne radar, thermal infrared scanners, and airborne geophysical systems can provide uniquely valuable geologic information under particular sets of geologic and climatic conditions, but are deemed too expensive for inclusion in all tunnel site evaluation programs. (Color illustrations reproduced in black and white)