HR: 17:45h
AN: V14B-08    [Abstracts]
TI: Blasts, Roars, and Chugs at Tungurahua Volcano
AU: * Ruiz, M C
EM: mruiz@email.unc.edu
AF: University of North Carolina, 3315 Mitchell Hall, Chapel Hill, NC 27599 United States
AU: Lees, J M
EM: jonathan_lees@unc.edu
AF: University of North Carolina, 3315 Mitchell Hall, Chapel Hill, NC 27599 United States
AU: Johnson, J B
EM: jeff.johnson@unh.edu
AF: University of New Hampshire, Climate Change Research Center, Durham, NH 03824 United States
AB: Tungurahua volcano began a significant strombolian style eruptive cycle in May, 2004, which peaked in July. Between June 30 and August 12, 2004, we installed temporary seismic and infrasonic instruments on the southwest, northwest and northeast flanks of the volcano. Three PASSCAL type portable stations, recording at 125 samples/s included two mid-band Guralp 40T's and one broadband Guralp 3T instruments. Microphones were 1 Hz Larson-Davis. We recorded hundreds of explosions with high fidelity on both the infrasonic and seismic instrumentation. The signals can be classified as: -Explosion events: impulsive short duration blasts on infrasound and spindle-shape long-duration seismic signals. Amplitudes of the blast signals span a four order range from 0.1 to 180 Pa (July 21, 03h32 GMT, the largest signal recorded on the NW station). -Roaring events, composed of complex seismic and infrasound signals with large frequency bandwidths at stations close to the vent. -Chugging events, composed of sawtooth shaped infrasound signals in the infrasound records which follow small explosion signals. These events correspond to tremor episodes observed on seismic records. -Man-made explosions recorded by one station and which can be used for calibration purposes. Cluster analysis and waveform similitude will be used to identify variation in vent physics over time and space.
DE: 8419 Eruption monitoring (7280)
DE: 7280 Volcano seismology (8419)
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2004 AGU Fall Meeting