HR: 1340h
AN: T33C-0570    [Abstracts]
TI: The TIPTEQ seismological network in Southern Chile - Studying the Seismogenic Coupling Zone
AU: * Haberland, C
EM: haber@geo.uni-potsdam.de
AF: University of Potsdam, Inst. of Geosciences, PO Box 60 15 53, Potsdam, 14415 Germany
AU: Rietbrock, A
EM: A.Rietbrock@liverpool.ac.uk
AF: University of Liverpool, Dept. of Earth & Ocean Sciences, 4 Brownlow Street, Liverpool, L69 3GP United Kingdom
AU: Lange, D
EM: dlange@geo.uni-potsdam.de
AF: University of Potsdam, Inst. of Geosciences, PO Box 60 15 53, Potsdam, 14415 Germany
AU: Bataille, K
EM: bataille@udec.cl
AF: Universidad de ConcepciA3n, Calle Chacabuco, ConcepciA3n, _ Chile
AU: Hofmann, S
EM: Sonja.Hofmann@dkrz.de
AF: University of Hamburg, Institut fA¬r Geophysik, BundesstraAYe 55, Hamburg, 20146 Germany
AU: Dahm, T
EM: dahm@dkrz.de
AF: University of Hamburg, Institut fA¬r Geophysik, BundesstraAYe 55, Hamburg, 20146 Germany
AU: Scherbaum, F
EM: fs@geo.uni-potsdam.de
AF: University of Potsdam, Inst. of Geosciences, PO Box 60 15 53, Potsdam, 14415 Germany
AU: Tilman, F
EM: tilmann@esc.cam.ac.uk
AF: University of Cambridge, Madingley Road, Cambridge, CB3 0EZ United Kingdom
AU: Hermosilla, G
EM: ghermosi@udec.cl
AF: Universidad de ConcepciA3n, Calle Chacabuco, ConcepciA3n, _ Chile
AU: Group, T S
EM: haber@geo.uni-potsdam.de
AF: University of Potsdam, Inst. of Geosciences, PO Box 60 15 53, Potsdam, 14415 Germany
AB: Subduction zones generate the world's largest and most destructive earthquakes. Understanding the factors leading to these earthquakes in the coupling zone of convergent margins and their interrelation with surface deformation are the main aims of the international and interdisciplinary research initiative TIPTEQ (From The Incoming Plate To megaThrust EarthQuake Processes) which is financed by the German Ministry for Education and Research (BMBF). These aims shall be achieved by obtaining high resolution images of the seismogenic zone and the forearc structure, which will form the base for identifying the processes involved. Our studies focus spatially on the nucleation zone of the Mw=9.5 1960 Chile earthquake, the worldwide largest instrumentally ever recorded earthquake. Within this project a large temporary seismological network is installed in southern Chile since Nov. 2004, covering the forearc between 37° and 39°S. It consists of 120 digitally recording and continuously running seismic stations equipped with short period sensors. The network covers the forearc between 37° and 39°S. The onshore network is complemented by 10 ocean bottom seismometers/hydrophones (OBS/OBH), and the stations (except for 20 stations which will operate until October 2005) were in operation until July 2005. The network is characterized by very short station spacings in the centre which will assure an increased quantity of P and S phase onset times and which will achieve the observation of the whole wavefield (coherent waveforms). A second network of 20 onshore and 20 offshore stations is installed at and around Chiloe Island for a one year period. Until now we collected about 1.2 TByte of data. First steps of the data processing are the event detection, the onset time picking, and the localisation of the (local) earthquakes (catalog). Later steps include the determination of the velocity and attenuation structure (tomography), the analysis of the stress field by moment tensor inversion, the analysis of later phases such as guided waves and scattered/converted/reflected arrivals, the analysis of teleseismic recordings (receiver functions, anisotropy), and many more. The results will be jointly interpreted with the findings of controlled source seismic studies, magnetotelluric measurements, and surface geological studies. Each day 2 to 3 local earthquakes and several teleseismic events were recorded. We present first results including data examples, seismicity distribution, and first 1D velocity models of this ongoing research project. Most of the crustal seismicity in the northern network is concentrated in two clusters close to the coast line; Benioff seismicity can be found down to 100 km depth. Between 41.5° and 43.5° S (at and around Chiloe Island) we also found several earthquakes in the continental (forearc) crust and in the downgoing slab.
DE: 3613 Subduction zone processes (1031, 3060, 8170, 8413)
DE: 7240 Subduction zones (1207, 1219, 1240)
DE: 7294 Seismic instruments and networks (0935, 3025)
DE: 8104 Continental margins: convergent
DE: 8120 Dynamics of lithosphere and mantle: general (1213)
SC: Tectonophysics [T]
MN: Fall Meeting 2005