VOLCANIC MASS FLOWS SUCH AS PYROCLASTIC DENSITY CURRENTS LAHARS DEBRIS AVALANCHES AND LAVA FLOWS ARE RESPONSIBLE FOR THE MOST FATALITIES DURING OR BETWEEN VOLCANIC ERUPTIONS. HAZARD ASSESSMENTS OF THESE EVENTS AT ACTIVE VOLCANOES ARE PREDOMINANTLY BASED ON COMPUTATIONAL MODELS OF VOLCANIC MASS FLOWS FOR WHICH THE ABILITY TO EFFECTIVELY SIMULATE A FLOW CRITICALLY DEPENDS ON THE CHOICE OF INPUT PARAMETERS. THE TOPOGRAPHY AT THESE VOLCANOES LARGELY CONTROLS THE DYNAMICS OF VOLCANIC MASS FLOWS AND RUGGED TERRAINS CAN GREATLY AFFECT THE FLOW MOBILITY METRICS (VOLUME INUNDATION AREAS RUNOUT DISTANCES) AND FINAL IMPACTS OF THESE EVENTS. HIGH-RESOLUTION DIGITAL ELEVATION MODELS (DEMS) CAN GENERATE ACCURATE NUMERICAL TOPOGRAPHY AND CAPTURE RAPID TOPOGRAPHIC CHANGES ASSOCIATED WITH VOLCANIC ACTIVITY. IN THIS PROPOSED RESEARCH WE WILL INVESTIGATE THE RELATIONSHIPS BETWEEN FLOW MOBILITY METRICS OF RECENT VOLCANIC MASS FLOW EVENTS GENERATED AT FIVE SELECTED ACTIVE VOLCANOES (VOLCAN DE COLIMA IN MEXICO; CALBUCO IN CHILE; NEVADO DEL RUIZ IN COLUMBIA MOMOTOMBO IN NICARAGUA AND MERAPI IN INDONESIA) AND THE KEY PRE- AND SYN-ERUPTIVE TOPOGRAPHIC PARAMETERS (E.G. SLOPE CURVATURE SURFACE ROUGHNESS AND CHANNEL GEOMETRIES) RESOLVED ON A SET OF LOW- AND HIGH-RESOLUTION DEMS. THIS REPRESENTS A GREAT OPPORTUNITY TO BETTER UNDERSTAND THE PROCESSES ASSOCIATED WITH VOLCANIC MASS FLOWS DURING AND BETWEEN ERUPTIONS AND TO IMPROVE THEIR MITIGATION AND HAZARD ASSESSMENT. TIME-DEPENDENT DATA SETS OF VARIOUS REMOTE SENSING TOOLS AND PRODUCTS AVAILABLE THROUGH NASA AND OTHER EUROPEAN SPACE AGENCIES WILL BE USED TO GENERATE LOW- AND HIGH-RESOLUTION DEMS TO ENCOMPASS POTENTIAL FLOW HAZARD AREAS AND CAPTURE TOPOGRAPHIC CHANGES OVER TIME. THE SETS OF HIGH-RESOLUTION DEMS WILL BE USED TO TEST THE SENSITIVITY OF SOME STANDARD VOLCANIC MASS FLOW MODELS AND INVESTIGATE HOW DEM ACCURACY AFFECTS THE HAZARD POTENTIAL OF THESE HAZARDOUS FLOWS. THESE DATA WILL BE USED TO DEMONSTRATE THE TREMENDOUS POTENTIAL OF GENERATING AND USING ENHANCED REMOTE SENSING TOOLS FOR VOLCANIC MASS FLOW HAZARDS AND RISK MANAGEMENT.