HR: 0800h
AN: V31B-0499    [Abstracts]
TI: TITAN2D Analyses of Dome-Collapse Pyroclastic Flows on Montserrat
AU: Hidayat, D
EM: hidayat@geosc.psu.edu
AF: Pennsylvania State University, 503 Deike Building, University Park, PA 16802, United States
AU: Widiwijayanti, C
EM: cwidiwij@geosc.psu.edu
AF: Pennsylvania State University, 503 Deike Building, University Park, PA 16802, United States
AU: * Voight, B
EM: voight@ems.psu.edu
AF: Pennsylvania State University, 503 Deike Building, University Park, PA 16802, United States
AU: Patra, A
EM: voight@ems.psu.edu
AF: University of Buffalo - Department of Mechanical & Aerospace Engineering, University Of Buffalo, Buffalo, NY 14260, United States
AU: Pitman, E
EM: voight@ems.psu.edu
AF: University of Buffalo: Department of Mathematics, University of Buffalo, Buffalo, NY 14260, United States
AB: Pyroclastic flows caused tens of thousands of deaths in the 20th century, partly due to lack of hazard maps. Toward resolution of this issue we have tested the model code TITAN2D (Patra et al. 2004), compared output to a unique database from Soufriere Hills Volcano, Montserrat, and used it for crisis assessments. TITAN-2D is a map plane (depth averaged) simulator of granular flow and yields mass distributions over a DEM. Two Coulomb frictional parameters control behaviour and Montserrat calibrations on small volume flows suggests basal friction between 7o and 17o. Many tens of simulations were run, using combinations of flow volume (2 to 40 Mm3), basal friction (5-12o), apparent internal friction (15-25o). An advantage is that the flow kinematics are captured, so that the dynamics of flow can be examined spatially from frame to frame, or as a movie. The full story is not merely in the final deposit map, and a hazard map should include not only final deposit, but also areas inundated by moving debris prior to deposition. Simulations from TITAN2D were important for analysis of the Jan-Mar 2007 crisis because they showed that any large mass released on the NW slope would be strongly partitioned, because of local topography. The simulations made it doubtful that a Belham River flow of large size (>20 Mm3 ) could be generated, because of partitioning of much of the collapsed mass to the north and east. This limited runout. Further, the runs suggested that much of the surge generated by the partitioned mass would likely be released early and move NE-NNW, rather than down the populated Belham. These effects were interpreted to greatly reduce the down-valley surge risk. This research is fostering improved understanding and computer code enhancements that should make the method more effective for hazards applications. NSF research support.
DE: 8414 Eruption mechanisms and flow emplacement
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting