HR: 1340h
AN: T33C-0568    [Abstracts]
TI: 3-Component Reflection Seismic Survey Across the Seismogenic Coupling Zone in Chile (Project TIPTEQ)
AU: Micksch, U
EM: micksch@gfz-potsdam.de
AF: GeoForschungsZentrum Potsdam, Telegrafenberg, Potsdam, 14473 Germany
AU: Gross, K
T33C-0568 AF: Freie Universität Berlin, Fachrichtung Geophysik, Malteserstrasse 74-100, Berlin, 12249 Germany
AU: Buske, S
T33C-0568 AF: Freie Universität Berlin, Fachrichtung Geophysik, Malteserstrasse 74-100, Berlin, 12249 Germany
AU: * Krawczyk, C M
T33C-0568 AF: GeoForschungsZentrum Potsdam, Telegrafenberg, Potsdam, 14473 Germany
AU: Stiller, M
T33C-0568 AF: GeoForschungsZentrum Potsdam, Telegrafenberg, Potsdam, 14473 Germany
AU: Wigger, P
T33C-0568 AF: Freie Universität Berlin, Fachrichtung Geophysik, Malteserstrasse 74-100, Berlin, 12249 Germany
AU: Araneda, M
T33C-0568 AF: SEGMI, San Sebastian 2750, Of. 704, Las Condes, Santiago, 6760197 Chile
AU: Bataille, K
T33C-0568 AF: Universidad de Concepción, Dep. Ciencias de la Tierra, Concepción, 160-C Chile
AU: Bribach, J
T33C-0568 AF: GeoForschungsZentrum Potsdam, Telegrafenberg, Potsdam, 14473 Germany
AU: Lüth, S
T33C-0568 AF: GeoForschungsZentrum Potsdam, Telegrafenberg, Potsdam, 14473 Germany
AU: Lüth, S
T33C-0568 AF: Freie Universität Berlin, Fachrichtung Geophysik, Malteserstrasse 74-100, Berlin, 12249 Germany
AU: Mechie, J
T33C-0568 AF: GeoForschungsZentrum Potsdam, Telegrafenberg, Potsdam, 14473 Germany
AU: Schulze, A
T33C-0568 AF: GeoForschungsZentrum Potsdam, Telegrafenberg, Potsdam, 14473 Germany
AU: Shapiro, S A
T33C-0568 AF: Freie Universität Berlin, Fachrichtung Geophysik, Malteserstrasse 74-100, Berlin, 12249 Germany
AU: Ziegenhagen, T
T33C-0568 AF: GeoForschungsZentrum Potsdam, Telegrafenberg, Potsdam, 14473 Germany
AB: The TIPTEQ project (from The Incoming Plate to mega-Thrust EarthQuake processes) studies processes which generate mega-thrust earthquakes at convergent plate margins, with the Chilean subduction zone as natural laboratory. The seismogenic coupling zones at convergent margin plate interfaces harbour some 90% of the global seismicity, and in the case of Chile, the hypocenter of the largest historically recorded earthquake in 1960 (Mw = 9.5). The rupture started at 38° S with a hypocentral depth of some 30 km below the continental forearc and continued towards the south for approximately 1000 km. The active seismic experiment component of TIPTEQ crosses the 1960 earthquake hypocenter. The survey consists of a 95 km long near-vertical reflection seismic profile shot in January 2005. 180 three-component geophones were deployed along an 18 km long spread, moving 4.5 km in a daily roll-along. Explosive shots, with a spacing of 1.5 km, allow an up to 8-fold CDP coverage. The W-E trending line runs across part of the Central Valley and continues over the coastal cordillera towards the Pacific. The seismic line shows good reflectivity and internal structures of the accretionary wedge and the plate interface. The down-going plate is clearly visible at c. 8 s TWT near the coast, reaching 17 s TWT at the eastern end of the profile. Two more experiment configurations were applied in addition: An expanding spread profiling setup aims at the down-dip limit of the seismogenic coupling zone at 30-50 km depth to image the hypocenter of the 1960 earthquake in more detail (10-fold coverage); a SH experiment configuration (1-fold coverage) served as a pilot study to test SH-wave generation in a crustal regime. Using the three component data, S-wave images could yield an improved picture of the petrophysical contrasts within the subduction zone. We present the results from poststack- and prestack-migration of the near-vertical reflection experiment, as well as a first interpretation of the obtained structural inventory. These results provide a high-resolution image of the subduction zone setting at 38° S and will be discussed with special focus on the seismogenic coupling zone and a possible subduction channel.
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