HR: 1330h
AN: S32A-0833    [PDF]
TI: A Teleseismic Study Across the Iapetus Suture Zone in Ireland: ISLE - the Irish Seismic Lithospheric Experiment
AU: * Do, V C
EM: vcd@cp.dias.ie
AF: Dublin Institute for Advanced Studies, 5 Merrion Square, Dublin, 2 Ireland
AU: Readman, P W
EM: pr@cp.dias.ie
AF: Dublin Institute for Advanced Studies, 5 Merrion Square, Dublin, 2 Ireland
AU: O'Reilly, B M
EM: bor@cp.dias.ie
AF: Dublin Institute for Advanced Studies, 5 Merrion Square, Dublin, 2 Ireland
AU: Landes, M
EM: Michael.Landes@gpi.uni-karlsruhe
AF: Geophysical Institute, University of Karlsruhe, Karlsruhe, 76187 Germany
AU: Ritter, J R
EM: Joachim.Ritter@gpi.uni-karlsruhe
AF: Geophysical Institute, University of Karlsruhe, Karlsruhe, 76187 Germany
AU: Hauser, F
EM: Franz.Hauser@gpi.uni-karlsruhe
AF: Geophysical Institute, University of Karlsruhe, Karlsruhe, 76187 Germany
AB: Anomalous travel time residuals were observed in southern Ireland for teleseismic P-waves from earthquakes and nuclear tests during the VARNET-96 controlled source experiment. Heterogeneities in the derived crustal structure cannot explain these so that most of the variation must originate below the crust. This present project is designed to more clearly define the extent of the P-wave residuals, and primarily to test the theory that seismic anisotropy in the sub-crustal mantle is the cause of these residuals. The experiment is designed to observe shear wave splitting, particularly of the S and SKS phases to see if anisotropic effects can be observed. Any resolved anisotropy may be due to transpressive effects resulting from the closure of the Iapetus Ocean at ca 400 Ma, or to the more recent stress history of the lithosphere. Surface waves from regional seismic events will also be studied in addition to wave attenuation. Seismic tomographic imaging with P- and S-waves will determine the 3-D structure of the crust and upper mantle. Additionally, a receiver function analysis will be undertaken to characterise seismic discontinuities at depth. Fourteen broadband seismometers from the Dublin Institute for Advanced Studies and eight short-period instruments from the GFZ Potsdam have been deployed to straddle the supposed line of the Iapetus Suture and the region of the observed P-wave travel-time anomaly. Data examples and preliminary analyses will be shown.
DE: 7200 SEISMOLOGY
DE: 7218 Lithosphere and upper mantle
DE: 8102 Continental contractional orogenic belts
DE: 9335 Europe
DE: 9614 Paleozoic
SC: Seismology [S]
MN: 2003 Fall Meeting