Estimated travel time of mudflows at Mount Hood, Oregon

Volcanic hazard maps are used to inform planners, policy-makers, and the public of the areas potentially impacted by volcanic hazards. We describe the design and production of a three-dimensional (3D) volcanic hazard map showing lahar travel times at Mount Hood, Oregon. The creation of this map involved the application of innovative techniques, including (a) an analytical model for computing lahar travel time isochrones; (b) a terrain tiling system for 3D modeling software; (c) the modeling of roads, rivers, and other linear features as 3D tubes to improve visibility; and (d) progressive terrain bending to create a top-down perspective in the foreground and an oblique perspective in the background. A user study (documented in a separate article) confirmed that the 3D map effectively shows the extent and travel time of potential lahars, allowing readers to choose better escape routes than with a conventional two-dimensional map.