HR: 0800h
AN: V31E-0707    [Abstracts]
TI: Ash plume dynamics at Santiaguito volcano, Guatemala, from thermal and high resolution video
AU: * Patrick, M
EM: mpatrick@mtu.edu
AF: Dept. Geological and Mining Engineering and Sciences, Michigan Tech University, 1400 Townsend Drive, Houghton, MI 49931, United States
AU: Varley, N
EM: nick@ucol.mx
AF: Facultad de Ciencias, Universidad de Colima, Av. 25 de Julio #965, Col. San Sebastià¡n, Apdo. Postal 25, Colima, Col CP 28045, Mexico
AU: Ramos, E
EM: eramos@mtu.edu
AF: Geology Department, University of Puerto Rico Mayaguez, PO Box 9017, Mayaguez, PR 00681, Puerto Rico
AU: Blankenbicker, A
EM: rblanken@mtu.edu
AF: Dept. Geological and Mining Engineering and Sciences, Michigan Tech University, 1400 Townsend Drive, Houghton, MI 49931, United States
AU: Johnson, J
EM: jeff.johnson@ees.nmt.edu
AF: Department of Earth and Environmental Science New Mexico Institute of Mining and Technology, 801 Leroy Place, Socorro, NM 87801, United States
AB: The regular (1-2 per hour) explosion plumes at Santiaguito volcano provide a valuable opportunity to track ash plume dynamics continuously from vent levels to neutral buoyancy heights, permitting a rare opportunity to analyze virtually the entire rise lifespan of an eruption plume. In January and June, 2007, we imaged 184 plumes at Santiaguito at frame rates of 7.5-30 fps, using both a thermal (FLIR) camera and a conventional camcorder situated at the Santiaguito observatory (6.5 km distance) and a second thermal (Variocam) camera at Santa Maria summit (2.5 km distance). The plumes we analyzed had near-vent velocities of 5-15 m/s, resulting in neutral buoyancy heights of approx. 0.5 to 2 km. Initial analyses of plume motion and dimensions suggest that bulk densities of the plume attain near-ambient values within a few hundred meters height, suggesting rapid and efficient air entrainment in initial stages of the plume rise. In a qualitative sense, the thermal data show daily variations in January in the character of the eruption plumes, ranging from robust, impulsive plumes with a well- developed plume front to more diffuse, emergent behaviors. We are currently investigating how these trends in velocity and character relate to concomitant infrasound and seismicity. It appears as though the relatively low intensity infrasound pressures associated with explosions (< few Pa at 1 km) reflects relatively low inertia at the vent and a plume that is largely buoyancy-driven.
DE: 8414 Eruption mechanisms and flow emplacement
DE: 8419 Volcano monitoring (7280)
DE: 8428 Explosive volcanism
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting