HR: 1330h
AN: V23A-11    [Abstracts]
TI: A Preliminary Study of Real-Time Seismic Event Amplitudes From the CALIPSO Borehole Dataset, Montserrat, 2002-2003
AU: * Coleman, K A
EM: kxs03@uark.edu
AF: University of Arkansas, 113 Ozark Hall, Fayetteville, AR 72701 United States
AU: Mattioli, G S
EM: mattioli@uark.edu
AF: University of Arkansas, 113 Ozark Hall, Fayetteville, AR 72701 United States
AB: The Caribbean Andesite Lava Island Precise-Geodetic Seismic Observatory (CALIPSO) project installed instruments at four sites around the Soufriere Hills Volcano beginning in December 2002. The instruments include Sacks-Evertson strainmeter, borehole tilt meter, borehole seismometers and continuous GPS with the borehole instruments installed at a depth of ~200m. Two seismometers and three strainmeters were operating during the July 12-13, 2003 lava dome collapse and subsequent vulcanian explosive events. The seismometers recorded hybrid swarms beginning one week prior to the eruption and intensifying through July 11th. By the morning of July 12th, the discrete events had merged into a continuous tremor event. Real-time Seismic Amplitude Measure (RSAM) is an analysis method that computes the average amplitude of the seismic signals to give a measure of the total seismic energy in the volcanic system over a set period of time. This method is particularly effective during volcanic events and other periods of intense seismic activity because it is not limited by the requirement of separating the events. RSAM time plots will be created from the archived data starting with the July 12-13, 2003 event and continuing backward through time until no significant seismic energy is observed. Periods of high energy on the RSAM plots will be examined closely to identify event types and determine hypocenter locations. These data will be compared with other data from CALIPSO and the Montserrat Volcano Observatory (e.g. surface deformation) to examine precursory phenomena prior to the major collapse event.
DE: 1299 General or miscellaneous
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2005 Joint Assembly