HR: 09:30h
AN: V41B-07    [Abstracts]
TI: Eruption dynamics at the active Santiaguito Dome inferred from a multidisciplinary geophysical experiment
AU: * Johnson, J B
EM: jeff.johnson@unh.edu
AF: Department of Earth Sciences, University of New Hampshire, Durham, NH 03824, United States
AU: Varley, N
EM: nick@ucol.mx
AF: University of Colima, Mexico,
AU: Sanderson, R
EM: rwn5@cisunix.unh.edu
AF: Department of Earth Sciences, University of New Hampshire, Durham, NH 03824, United States
AU: Gerst, A
EM: Alexander.Gerst@zmaw.de
AF: University of Hamburg, Germany,
AU: Lees, J
EM: jonathan.lees@unc.edu
AF: Department of Geological Sciences, University of North Carolina, Durham, NC , United States
AU: Dalton, M
EM: mpdalton@mtu.edu
AF: Department of Geological and Mining Engineering and Sciences, Michigan Technological University, Houghton, MI , United States
AU: Marcillo, O
EM: oed4@cisunix.unh.edu
AF: Department of Earth Sciences, University of New Hampshire, Durham, NH 03824, United States
AU: Every, S
EM: severy@unh.edu
AF: Department of Earth Sciences, University of New Hampshire, Durham, NH 03824, United States
AU: Normand, J
EM: joshuan@cisunix.unh.edu
AF: Department of Earth Sciences, University of New Hampshire, Durham, NH 03824, United States
AU: Ruiz, M
EM: mruiz@email.unc.edu
AF: Department of Geological Sciences, University of North Carolina, Durham, NC , United States
AB: Santiaguito Dome, which lies in the shadow of its parent stratovolcano (Santa Maria, Guatemala), has been effusing and exploding for more than eight decades. Pyroclastic emissions from the currently active Caliente Vent are characterized by ash and ballistic-rich emissions at least every hour, with vapor plumes that reach more than a kilometer above the vent. Such activity is recently accompanied by slow effusion of a dacitic block lava flow, which overtops the shallow 200-m-diameter crater and flows down the flanks of the cone. We are studying the mechanics of this explosive activity with an arsenal of geophysical sensors because of the unparalleled view into the crater from the Santa Maria summit vantage 1200 m above. Data collected in January 2007 provides us with the opportunity to quantify the energy budget for small-magnitude pyroclastic eruptions involving a silica-rich (dacitic) magma. Specifically, we are integrating seismic, infrasonic, thermal imaging, gas flux (SO₂) imaging, high resolution video, and doppler radar observations to assess the temporal chronology of an eruption beginning with pre-eruption seismicity (apparent a few seconds to tens of seconds before the eruption onset), followed by subsequent infrasound radiation, and multi-phase material flux out through the vent. We are integrating these diverse data streams with the goal to better understand the location of various elastic energy sources and to provide more insight into the complex geometry of the crater and conduit system. Integrated measurements are used to assess the kinetic energy and thermal flux with an end goal of using elastic wavefield studies to remotely quantify eruption intensity at this type of potentially hazardous volcano.
UR: http:earth.unh.edu/johnson/SANTIAGUITO/santiaguito.htm
DE: 8414 Eruption mechanisms and flow emplacement
DE: 8419 Volcano monitoring (7280)
DE: 8428 Explosive volcanism
DE: 8494 Instruments and techniques
SC: Volcanology, Geochemistry, and Petrology [V]
MN: 2007 Joint Assembly