Journal of Volcanology and Geothermal Research, 2008
... The volcanic hazard map of El Chichón is based on detailed field work that documented twelve ... more ... The volcanic hazard map of El Chichón is based on detailed field work that documented twelve eruptions during the last 8000 ... These eruptions have produced pyroclastic fall, surge, flow andlahar deposits. ... 3 km from the crater, with no effect on populations around the volcano. ...
Volcán Citlaltépetl (Pico de Orizaba) with an elevation of 5,675 m is the highest volcano in Nort... more Volcán Citlaltépetl (Pico de Orizaba) with an elevation of 5,675 m is the highest volcano in North America. Its most recent catastrophic events involved the production of pyroclastic flows that erupted approximately 4,000, 8,500, and 13,000 years ago. The distribution of mapped deposits from these eruptions gives an approximate guide to the extent of products from potential future eruptions. Because the topography of this volcano is constantly changing computer simulations were made on the present topography using three computer algorithms: energy cone, FLOW2D, and FLOW3D. The Heim Coefficient (μ), used as a code parameter for frictional sliding in all our algorithms, is the ratio of the assumed drop in elevation (H) divided by the lateral extent of the mapped deposits (L). The viscosity parameter for the FLOW2D and FLOW3D codes was adjusted so that the paths of the flows mimicked those inferred from the mapped deposits. We modeled two categories of pyroclastic flows modeled for the level I and level II events. Level I pyroclastic flows correspond to small but more frequent block-and-ash flows that remain on the main cone. Level II flows correspond to more widespread flows from catastrophic eruptions with an approximate 4,000-year repose period. We developed hazard maps from simulations based on a National Imagery and Mapping Agency (NIMA) DTED-1 DEM with a 90 m grid and a vertical accuracy of ±30 m. Because realistic visualization is an important aid to understanding the risks related to volcanic hazards we present the DEM as modeled by FLOW3D. The model shows that the pyroclastic flows extend for much greater distances to the east of the volcano summit where the topographic relief is nearly 4,300 m. This study was used to plot hazard zones for pyroclastic flows in the official hazard map that was published recently.
Abstract Volcanic risk is increasing as populations grow in active volcanic regions, and as natio... more Abstract Volcanic risk is increasing as populations grow in active volcanic regions, and as national economies become increasingly intertwined. In addition to their significance to risk, volcanic eruption processes form a class of multiphase fluid dynamics with rich physics on ...
Avalanches and debris flows, often associated with volcanic activity or heavy rainfall on overste... more Avalanches and debris flows, often associated with volcanic activity or heavy rainfall on oversteepened slopes, pose a significant risk to those living on the flanks of volcanoes. In 1985, debris flows originating from the summit of Ruiz volcano in Colombia overran entire ...
ABSTRACT We address the uncertainty inherent in modeling and computational simulations of geophys... more ABSTRACT We address the uncertainty inherent in modeling and computational simulations of geophysical mass flows. This uncertainty arises from unresolved physics, modeling simplifications, errors in terrain data or constitutive parameters, and the inaccuracies of any numerical method. The errors must be incorporated directly into the modeling and computations, and ensembles of solutions to the deterministic model equations, coupled to statistical analysis, are necessary to provide meaningful results for hazard assessment and risk mitigation associated with geophysical mass flows such as avalanches and landslides. In recent years a set of depth averaged equations (the Savage-Hutter model) with simple constitutive modeling assumptions has come into wide usage. In earlier work we developed the TITAN toolset that uses state of the art numerical methodology (high performance computing, adaptive gridding, etc.) to construct approximate solutions to these systems of equations for modeling flow over natural terrain. We describe in this contribution our efforts at incorporating uncertainty representations into this toolset. We use the recently developed methodology of polynomial chaos to represent uncertainty in the outputs based on input data uncertainty. In applying the polynomial chaos methodology to such systems we have had to overcome a series of technical difficulties. We will describe our solutions to each of these obstacles. Real-world results showing the comparison between model outputs and data collected in the field will be used in illustration.
Geological Society of America Special Papers, 2010
Page 1. Geological Society of America Special Papers doi: 10.1130/2010.2464(14) 2010;464;281-291 ... more Page 1. Geological Society of America Special Papers doi: 10.1130/2010.2464(14) 2010;464;281-291 Geological Society of America Special Papers Michael F. Sheridan, Abani K. Patra, Keith Dalbey and Bernard Hubbard using ...
During late December 2000, the giant volcano Popocatépetl near Mexico City exhibited violent expl... more During late December 2000, the giant volcano Popocatépetl near Mexico City exhibited violent explosions. About 20,000 people evacuated their homes for a week to 10 days before returning. On January 22, 2001, an even larger explosion occurred. This article explores the short-term hazards that are probable at this volcano.
Journal of Volcanology and Geothermal Research, 2008
... The volcanic hazard map of El Chichón is based on detailed field work that documented twelve ... more ... The volcanic hazard map of El Chichón is based on detailed field work that documented twelve eruptions during the last 8000 ... These eruptions have produced pyroclastic fall, surge, flow andlahar deposits. ... 3 km from the crater, with no effect on populations around the volcano. ...
Volcán Citlaltépetl (Pico de Orizaba) with an elevation of 5,675 m is the highest volcano in Nort... more Volcán Citlaltépetl (Pico de Orizaba) with an elevation of 5,675 m is the highest volcano in North America. Its most recent catastrophic events involved the production of pyroclastic flows that erupted approximately 4,000, 8,500, and 13,000 years ago. The distribution of mapped deposits from these eruptions gives an approximate guide to the extent of products from potential future eruptions. Because the topography of this volcano is constantly changing computer simulations were made on the present topography using three computer algorithms: energy cone, FLOW2D, and FLOW3D. The Heim Coefficient (μ), used as a code parameter for frictional sliding in all our algorithms, is the ratio of the assumed drop in elevation (H) divided by the lateral extent of the mapped deposits (L). The viscosity parameter for the FLOW2D and FLOW3D codes was adjusted so that the paths of the flows mimicked those inferred from the mapped deposits. We modeled two categories of pyroclastic flows modeled for the level I and level II events. Level I pyroclastic flows correspond to small but more frequent block-and-ash flows that remain on the main cone. Level II flows correspond to more widespread flows from catastrophic eruptions with an approximate 4,000-year repose period. We developed hazard maps from simulations based on a National Imagery and Mapping Agency (NIMA) DTED-1 DEM with a 90 m grid and a vertical accuracy of ±30 m. Because realistic visualization is an important aid to understanding the risks related to volcanic hazards we present the DEM as modeled by FLOW3D. The model shows that the pyroclastic flows extend for much greater distances to the east of the volcano summit where the topographic relief is nearly 4,300 m. This study was used to plot hazard zones for pyroclastic flows in the official hazard map that was published recently.
Abstract Volcanic risk is increasing as populations grow in active volcanic regions, and as natio... more Abstract Volcanic risk is increasing as populations grow in active volcanic regions, and as national economies become increasingly intertwined. In addition to their significance to risk, volcanic eruption processes form a class of multiphase fluid dynamics with rich physics on ...
Avalanches and debris flows, often associated with volcanic activity or heavy rainfall on overste... more Avalanches and debris flows, often associated with volcanic activity or heavy rainfall on oversteepened slopes, pose a significant risk to those living on the flanks of volcanoes. In 1985, debris flows originating from the summit of Ruiz volcano in Colombia overran entire ...
ABSTRACT We address the uncertainty inherent in modeling and computational simulations of geophys... more ABSTRACT We address the uncertainty inherent in modeling and computational simulations of geophysical mass flows. This uncertainty arises from unresolved physics, modeling simplifications, errors in terrain data or constitutive parameters, and the inaccuracies of any numerical method. The errors must be incorporated directly into the modeling and computations, and ensembles of solutions to the deterministic model equations, coupled to statistical analysis, are necessary to provide meaningful results for hazard assessment and risk mitigation associated with geophysical mass flows such as avalanches and landslides. In recent years a set of depth averaged equations (the Savage-Hutter model) with simple constitutive modeling assumptions has come into wide usage. In earlier work we developed the TITAN toolset that uses state of the art numerical methodology (high performance computing, adaptive gridding, etc.) to construct approximate solutions to these systems of equations for modeling flow over natural terrain. We describe in this contribution our efforts at incorporating uncertainty representations into this toolset. We use the recently developed methodology of polynomial chaos to represent uncertainty in the outputs based on input data uncertainty. In applying the polynomial chaos methodology to such systems we have had to overcome a series of technical difficulties. We will describe our solutions to each of these obstacles. Real-world results showing the comparison between model outputs and data collected in the field will be used in illustration.
Geological Society of America Special Papers, 2010
Page 1. Geological Society of America Special Papers doi: 10.1130/2010.2464(14) 2010;464;281-291 ... more Page 1. Geological Society of America Special Papers doi: 10.1130/2010.2464(14) 2010;464;281-291 Geological Society of America Special Papers Michael F. Sheridan, Abani K. Patra, Keith Dalbey and Bernard Hubbard using ...
During late December 2000, the giant volcano Popocatépetl near Mexico City exhibited violent expl... more During late December 2000, the giant volcano Popocatépetl near Mexico City exhibited violent explosions. About 20,000 people evacuated their homes for a week to 10 days before returning. On January 22, 2001, an even larger explosion occurred. This article explores the short-term hazards that are probable at this volcano.
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