Hydrothermal alteration which produces argillic and phyllic minerals has been shown to weaken volcanic edifices and increase the potential for debris flows (Crandell, 1971; Scott and others, 1995). We propose to use Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data, and the ASTER Global Digital Elevation Model (GDEM) database to compile hydrothermal alteration and slope-alteration hazard maps for display and distribution from the ASTER Volcanoes Archive (AVA; http://ava.jpl.nasa.gov/). The AVA, is a web-based server which currently supplies ASTER high-resolution JPEG images for approximately 1500 volcanoes worldwide. Approximately 800 of the volcanoes in the AVA database are large strato- and complex volcanoes that have significant vertical profiles allowing for the generation of potentially catastrophic debris flows (lahars). Hydrothermal alteration mapping will use Interactive Data Language (IDL) logical operators and ASTER VNIR-SWIR data (Mars and Rowan, 2006). Slope maps and drainages will be compiled from the ASTER GDEM using Envi and ARC-GIS software. The slope data and argillic- and phyllic-altered rock units will be used to compile slope-classified altered rock units for slopes 35 degrees. Products will include hydrothermally altered rock and slope-classified altered rock hazards maps that will also display major drainages and population density data (Bhaduri et al., 2007: http://www.ornl gov/sci/landscan/). Maps illustrating the possible extent of debris flows will be compiled from volume-based lahar source and flow modeling for volcanoes with high volumes of altered rocks and population density (Crowley et al., 2003; Iverson, et al., 1998). The alteration and hazard zone units will be available in geospatial formats such as raster geotiff, Arc GIS shape, and Google KMH georegistered files. The resulting global database will be useful for development and evacuation planning in populated areas that are vulnerable to debris flows.