HR: 17:40h
AN: S44A-06 INVITED     [Abstracts]
TI: Integration of Passive and Active Source Seismology: Mapping Lithospheric Structure Beneath Scotland
AU: * Knapp, J H
EM: knapp@geol.sc.edu
AF: University of South Carolina, Dept. Geological Sciences, Columbia, SC 29208 United States
AU: Asencio, E
EM: asencio@uprm.edu
AF: University of Puerto Rico, Dept. Geological Sciences, Mayaguez, PR 00681 United States
AU: Owens, T J
EM: owens@sc.edu
AF: University of South Carolina, Dept. Geological Sciences, Columbia, SC 29208 United States
AU: Helffrich, G
EM: george@gly.bris.ac.uk
AF: University of Bristol, Dept. Earth Sciences, Bristol, BS8 1RJ United Kingdom
AB: Upper mantle reflections (W and Flannan) beneath the northwestern British Isles are some of the best-known and most-studied examples of fine-scale heterogeneity within the mantle lithosphere. First observed on BIRPS (British Institutions Reflection Profiling Syndicate) marine deep seismic reflection profiles in the early 1980's, these reflectors have subsequently been imaged and correlated on additional reflection and refraction profiles in the offshore area of northern and western Scotland, but have not previously been reliably traced beneath the Scottish mainland. In addition, the age and tectonic significance of these features remains a subject of wide debate, due in part to the absence of robust characterization of the upper mantle velocity structure in this tectonically complex area. A key test of the origin of these mantle reflectors is their relationship to lithosphere-scale tectonic features, such as the Great Glen fault and the Iapetus suture, known from surface observations. Two passive-source arrays (RUSH I and RUSH II) were designed to evaluate the potential to image known mantle reflectors in the British Isles on passive-source data, and to potentially map these features beneath the mainland. Analysis of teleseismic data from an initial 7-station broadband deployment in northern Scotland (RUSH I) appears to support the viability of the technique. Preliminary analysis of the subsequent 23-station broadband array (RUSH II) suggests the subhorizontal W-reflector, in particular, can be traced continuously beneath the mainland, and may truncate the Great Glen fault at depth.
DE: 7203 Body waves
DE: 7205 Continental crust (1219)
DE: 7218 Lithosphere (1236)
DE: 8110 Continental tectonics: general (0905)
SC: Seismology [S]
MN: Fall Meeting 2005