HR: 11:20h
AN: T42A-05    [Abstracts]
TI: Imaging the Seismogenic Coupling Zone in Chile: The 3-Component Reflection Seismic Survey of Project TIPTEQ
AU: * Krawczyk, C M
EM: lotte@gfz-potsdam.de
AF: GeoForschungsZentrum Potsdam, Telegrafenberg, Potsdam, 14473 Germany
AU: Micksch, U
T42A-05 AF: GeoForschungsZentrum Potsdam, Telegrafenberg, Potsdam, 14473 Germany
AU: Gross, K
T42A-05 AF: Freie Universität Berlin, Fachrichtung Geophysik, Malteserstrasse 74-100, Berlin, 12249 Germany
AU: Buske, S
T42A-05 AF: Freie Universität Berlin, Fachrichtung Geophysik, Malteserstrasse 74-100, Berlin, 12249 Germany
AU: Stiller, M
T42A-05 AF: GeoForschungsZentrum Potsdam, Telegrafenberg, Potsdam, 14473 Germany
AU: Wigger, P
T42A-05 AF: Freie Universität Berlin, Fachrichtung Geophysik, Malteserstrasse 74-100, Berlin, 12249 Germany
AU: Araneda, M
T42A-05 AF: SEGMI, San Sebastian 2750, Of. 704 Las Condes, Santiago, 6760197 Chile
AU: Bataille, K
T42A-05 AF: Universidad de Concepción, Dep. Ciencias de la Tierra, Concepción, 160-C Chile
AU: Bribach, J
T42A-05 AF: GeoForschungsZentrum Potsdam, Telegrafenberg, Potsdam, 14473 Germany
AU: Lüth, S
T42A-05 AF: GeoForschungsZentrum Potsdam, Telegrafenberg, Potsdam, 14473 Germany
AU: Lüth, S
T42A-05 AF: Freie Universität Berlin, Fachrichtung Geophysik, Malteserstrasse 74-100, Berlin, 12249 Germany
AU: Mechie, J
T42A-05 AF: GeoForschungsZentrum Potsdam, Telegrafenberg, Potsdam, 14473 Germany
AU: Schulze, A
T42A-05 AF: GeoForschungsZentrum Potsdam, Telegrafenberg, Potsdam, 14473 Germany
AU: Shapiro, S A
T42A-05 AF: Freie Universität Berlin, Fachrichtung Geophysik, Malteserstrasse 74-100, Berlin, 12249 Germany
AU: Ziegenhagen, T
T42A-05 AF: GeoForschungsZentrum Potsdam, Telegrafenberg, Potsdam, 14473 Germany
AB: One of the main tasks in subduction zone research is that of the structural and petrophysical understanding of the seismogenic coupling zone, and especially its down-dip end. Here, mega-thrust earthquakes are suggested to initiate, but the trigger and processes that shape them are less understood. Amongst 13 sub-projects within TIPTEQ (from The Incoming Plate to mega-Thrust EarthQuake processes), the reflection seismic sub-project aims at the imaging and identification of processes in the seismogenic coupling zone of the present state of the ruptured plate interface at the southern Central Chilean margin. Together with the marine SPOC data, the newly acquired high-resolution 3-component reflection seismic land data will yield a reflection seismic section that will cover the entire seismogenic coupling zone. In addition, an expanding spread experiment component focuses on the down-dip limit (30-50 km depth). S-wave source signals were generated and S-waves obtained with 3-component recordings should yield an improved picture of the petrophysical contrasts within the subduction zone system. The first high-resolution reflection seismic section of the seismogenic coupling zone between the subducting Nazca Plate and the South American continent is presented. It shows that the sediment subduction mode observed offshore corresponds well with the landward reflection seismic extension towards the east at 38° 15' S. Structural evidence suggests that material is transported down in a subduction channel. From slow uplift of the Coastal Cordillera we conclude that basal accretion of parts of this material controls the seismic architecture and growth of the south Chilean crust. At present, almost no seismicity is observed along the entire, approximately 130 km wide seismogenic coupling zone, which could point to a higher coupling and stress accumulation in the region. We discuss underplating, forearc uplift and dehydration/serpentinisation processes at the top of the active subduction channel as key processes at the southern Central Chilean margin.
DE: 1242 Seismic cycle related deformations (6924, 7209, 7223, 7230)
DE: 3060 Subduction zone processes (1031, 3613, 8170, 8413)
DE: 7209 Earthquake dynamics (1242)
DE: 8123 Dynamics: seismotectonics
SC: Tectonophysics [T]
MN: Fall Meeting 2005