HR: 0800h
AN: T51A-0305    [Abstracts]
TI: Subduction in Central Kermadec: Crustal Structures from the Incoming Plate and the Arc- Backarc Region From Wide-Angle Seismics
AU: Scherwath, M
EM: mscherwath@ifm-geomar.de
AF: Leibniz-Institute of Marine Sciences IFM-GEOMAR, Wischhofstr. 1-3, Kiel, 24148, Germany
AU: * Kopp, H
EM: hkopp@ifm-geomar.de
AF: Leibniz-Institute of Marine Sciences IFM-GEOMAR, Wischhofstr. 1-3, Kiel, 24148, Germany
AU: Flueh, E R
EM: eflueh@ifm-geomar.de
AF: Leibniz-Institute of Marine Sciences IFM-GEOMAR, Wischhofstr. 1-3, Kiel, 24148, Germany
AU: Henrys, S A
EM: S.Henrys@gns.cri.nz
AF: GNS Science, 1 Fairway Drive Avalon PO Box 30-368, Lower Hutt, 5040, New Zealand
AB: The central part of the 2500-km long Tonga-Kermadec Trench is characterized by the subduction of the Louisville Ridge and unusually large seismicity approximately 200-300 km to the south of this ridge subduction. From this region we show preliminary results which have been derived from the recently acquired interpretation of seismic wide-angle reflection/refraction data. The data were collected along an almost 500-km long transect carried out in April 2007 using the R/V Sonne in order to determine the upper lithospheric structures of the incoming Pacific Plate and the overriding Australian Plate across the Colville and Kermadec Ridges. This transect lies immediately north of Raoul Island, the largest of the Kermadec Islands and which is presently a highly active volcano. This study is part of the MANGO project (Marine Geoscientific Inverstigations on the Input and Output of the Kermadec Subduction Zone) which comprises a 1000-km long working area north of New Zealand's North Island. It covers the transition from subduction of the Hikurangi Plateau in the south to erosive subduction of normal Pacific oceanic crust in the centre and thence accretionary subduction further north. Overall the subduction is accompanied by northward increasing seismicity. The aim of this project is to understand the transition throughout the different regimes, the variation of the structures to explain the accompanying seismicty, and the role and evolution of the stratovolcanoes. This will be achieved by analysing the structures of the sediment, crust and upper mantle and also material transfers from its input and output through subduction zone processes.
DE: 7218 Lithosphere (1236)
DE: 7240 Subduction zones (1207, 1219, 1240)
DE: 8124 Earth's interior: composition and state (1212, 7207, 7208, 8105)
DE: 8150 Plate boundary: general (3040)
DE: 8170 Subduction zone processes (1031, 3060, 3613, 8413)
SC: Tectonophysics [T]
MN: 2007 Fall Meeting