HR: 0800h
AN: T11A-1224    [Abstracts]
TI: David Glacier, North Victoria Land, 2003-04 Local Seismicity Monitoring Campaign
AU: * Danesi, S
EM: danesi@ingv.it
AF: INGV - Roma, Via di Vigna Murata, 605, Roma, RM 00143 Italy
AU: Bannister, S
EM: s.bannister@gns.cri.nz
AF: Institute of Geological & Nuclear Sciences, 41 Bell Road South, Lower Hutt, 30368 New Zealand
AU: Morelli, A
EM: morelli@bo.ingv.it
AF: INGV - Bologna, Via Donato Creti, 12, Bologna, BO 40135
AU: Hagerty, M
EM: m.hagerty@gns.cri.nz
AF: Institute of Geological & Nuclear Sciences, 41 Bell Road South, Lower Hutt, 30368 New Zealand
AU: Delladio, A
EM: delladio@ingv.it
AF: INGV - Roma, Via di Vigna Murata, 605, Roma, RM 00143 Italy
AU: Pagliuca, N M
EM: pagliuca@ingv.it
AF: INGV - Roma, Via di Vigna Murata, 605, Roma, RM 00143 Italy
AB: Low magnitude seismic activity has been recorded in the North Victoria Land area, Antarctica, by permanent seismographic stations operating in the region (Terra Nova Bay, TNV, Italy; Scott Base, SBA, New Zealand; Vanda, VNDA, USA), as well as by portable broadband arrays positioned in the Transantarctic Mountains. Previous studies of these events have located hypocentres beneath the David Glacier, one of the largest glaciers in the Ross Sea region. During the 2003-2004 austral summer a temporary broadband seismic array was placed in the David Glacier region, with the aim of improving the estimates of the hypocentral and source parameters, in an effort to discriminate between the possible source processes (e.g. brittle ice failure, basal shearing, fault slip). The temporary array involved siting nine portable seismic recorders on the few rock outcrops surrounding the target area, with a total array aperture of approximately 100 km. The array recorded continuously for more than 4 months, from November 2003 to February 2004. Preliminary location work, utilising the double difference technique, indicates that all of the located events lie close to the area known as the David Cauldron, where the bedrock beneath the glacier has a marked change in slope and where there is considerable surface crevassing. The main cluster of events extends spatially less than 5 km, and lies at the downstream side of the Cauldron. All other events lie within 10-15 km of the main event cluster, within the approximate outer boundary of the Cauldron. The tight nature of the event cluster, and its proximity to the Cauldron, suggest that the source process for these events likely involves basal shear or ice failure, rather than fault rupture beneath the glacier.
DE: 9310 Antarctica
DE: 7230 Seismicity and seismotectonics
DE: 7294 Instruments and techniques
DE: 7218 Lithosphere and upper mantle
SC: Tectonophysics [T]
MN: 2004 AGU Fall Meeting