TY - JOUR

T1 - Simulating the Development of Basaltic Volcanic Fields for Long-Term Hazard Assessment

AU - Connor, Charles

AU - Connor, Laura

AU - Germa, Aurélie

AU - Richardson, Jacob A.

AU - Molisee, Danielle D.

PY - 2017/12/14

Y1 - 2017/12/14

N2 - An important application of lava flow simulation is to model topography and surface geology in volcanic terrains with the goal of improving hazard assessments. We use a lava flow simulator, MOLASSES, coupled with codes modeling vent distribution, tephra dispersion and erosion to simulate the development of the surface geology and topography of basaltic volcanic fields. The simulation workflow begins by modeling the potential distribution of vents as a stochastic process using kernel density estimation, informed by geophysical models of the crust. Scoria cone dimensions, lava flow volume and thickness are then used to model multi-vent structures, breached scoria cones, and spatter cones. Tephra2, a tephra dispersion simulator is used to model medial deposition of tephra. MOLASSES is a cellular automata code that forecasts the dimensions of lava flows erupted at a point source on a digital elevation model. Lava and tephra are accumulated to construct topography, updating digital elevation models of the terrain. This topography is modified by erosion using the diffusion-advection equation and variable diffusivity for tephra, spatter and lava. Output from the simulator shows how the map geology of volcanic fields depends on vent density, volume of eruptive products, and the recurrence rate of volcanic activity. The potential for vent burial, which potentially biases hazard models, depends strongly on these factors. The erosion of scoria cones with time depends on vent density, and the likelihood of the scoria cone being re-surfaced by tephra fallout from younger adjacent cones. Our results suggest that quantitative treatment of geologic maps of volcanic fields using computer simulation will improve our understanding of the development of these basaltic volcanic fields and long-term hazard models.

AB - An important application of lava flow simulation is to model topography and surface geology in volcanic terrains with the goal of improving hazard assessments. We use a lava flow simulator, MOLASSES, coupled with codes modeling vent distribution, tephra dispersion and erosion to simulate the development of the surface geology and topography of basaltic volcanic fields. The simulation workflow begins by modeling the potential distribution of vents as a stochastic process using kernel density estimation, informed by geophysical models of the crust. Scoria cone dimensions, lava flow volume and thickness are then used to model multi-vent structures, breached scoria cones, and spatter cones. Tephra2, a tephra dispersion simulator is used to model medial deposition of tephra. MOLASSES is a cellular automata code that forecasts the dimensions of lava flows erupted at a point source on a digital elevation model. Lava and tephra are accumulated to construct topography, updating digital elevation models of the terrain. This topography is modified by erosion using the diffusion-advection equation and variable diffusivity for tephra, spatter and lava. Output from the simulator shows how the map geology of volcanic fields depends on vent density, volume of eruptive products, and the recurrence rate of volcanic activity. The potential for vent burial, which potentially biases hazard models, depends strongly on these factors. The erosion of scoria cones with time depends on vent density, and the likelihood of the scoria cone being re-surfaced by tephra fallout from younger adjacent cones. Our results suggest that quantitative treatment of geologic maps of volcanic fields using computer simulation will improve our understanding of the development of these basaltic volcanic fields and long-term hazard models.

UR - https://digitalcommons.usf.edu/geo_facpub/2121

UR - https://agu.confex.com/agu/fm17/meetingapp.cgi/Paper/232003

M3 - Article

JO - AGU Fall Meeting

JF - AGU Fall Meeting

ER -