HR: 0830h
AN: S41D-0118    [PDF]
TI: Seismoacoustic Study of Sedimentary Deformations in the Costa Rican Subduction Zone
AU: * Fekete, N
EM: nfekete@geomar.de
AF: SFB 574, C-A. University of Kiel Wischhofstr. 1-3., Kiel, 24148 Germany
AU: Spiess, V
EM:
AF: Marine Technology / Environmental Research, Dept. of Earth Science Klagenfurter Str. P.O.Box 33 04 40, Bremen, 28359 Germany
AU: Zuehlsdorff, L
EM:
AF: Marine Technology / Environmental Research, Dept. of Earth Science Klagenfurter Str. P.O.Box 33 04 40, Bremen, 28359 Germany
AU: Reston, T
EM:
AF: SFB 574, C-A. University of Kiel Wischhofstr. 1-3., Kiel, 24148 Germany
AU: Reston, T
EM:
AF: Geomar Research Centre, Wischhofstr. 1-3., Kiel, 24148 Germany
AB: R/V METEOR Research Cruise M54/1 in summer 2002 from Balboa (Panama) to Caldera (Costa Rica) aimed to image the near seafloor sedimentary structures of both the continental and oceanic plates of the Costa Rican Subduction Zone with multi-frequency seismo-acoustic methods (high resolution multichannel seismics, digital echosounder). The cruise was intended to supplement from Bremen University the marine geophysical, geological, geochemical and oceanographic data collected within Special Research Project 574: Fluids and Volatiles in Subduction Zones of the University of Kiel, and its objectives were to study 1) the volatile and material input into the sedimentary system on the oceanic plate, 2) the distribution of gas hydrates within the sediments, 3) possible pathways and resulting structures of fluid/gas escape and 4) the nature of shallow sedimentary deformations at subduction zones. Our poster contributes to the general understanding of fluid circulation and sedimentary processes in subduction zones. It addresses questions of sedimentology and tectonics at different segments of the continental and oceanic plates of the Costa Rican Subduction Zone, as seen from high resolution multichannel seismic and digital echosounder data. The following issues are addressed: - Seismic features of a proposed IODP transect; its sedimentary structures, BSR, gas and gas hydrate distribution; indications for massive subsidence and slope instability. - Normal fault deformation of the sedimentary cover of the oceanic plate and in the Costa Rican trench in high resolution seismic and acoustic data. - Deformation patterns over subducting seamounts (Jaco \& Parrita Scarps): a study of the different manifestations of sediment deformation and fault patterns that result from anomalous local compression, as seen in multichannel seismic data. - Geophysical indications of fluid venting, mud diapirism, and gas hydrate occurrance on the northern, smooth-floor continental domain (Mound Culebra) from multi-frequency seismo-acoustic investigations, indications of fluid pathways and consequences on local tectonic characteristics.
DE: 0935 Seismic methods (3025)
DE: 5102 Acoustic properties
DE: 8010 Fractures and faults
DE: 8045 Role of fluids
DE: 9355 Pacific Ocean
SC: Seismology [S]
MN: 2003 Fall Meeting