HR: 1330h
AN: T52C-0280    [PDF]
TI: Seismic Investigation of the D\'{e}collement Offshore Costa Rica
AU: * Schnabel, M
EM: mschnabel@geomar.de
AF: SFB 574, University of Kiel, Wischhofstr. 1-3, Kiel, 24148 Germany
AU: Flueh, E R
EM: eflueh@geomar.de
AF: SFB 574, University of Kiel, Wischhofstr. 1-3, Kiel, 24148 Germany
AU: Flueh, E R
EM: eflueh@geomar.de
AF: GEOMAR, Wischhofstr. 1-3, Kiel, 24148 Germany
AU: Klaeschen, D
EM: dklaeschen@geomar.de
AF: SFB 574, University of Kiel, Wischhofstr. 1-3, Kiel, 24148 Germany
AU: Klaeschen, D
EM: dklaeschen@geomar.de
AF: GEOMAR, Wischhofstr. 1-3, Kiel, 24148 Germany
AU: Zillmer, M
EM: mzillmer@geomar.de
AF: GEOMAR, Wischhofstr. 1-3, Kiel, 24148 Germany
AB: The convergent margin offshore Costa Rica is the focus of the investigations within the SFB 574 "Volatiles and Fluids in Subduction Zones: Climate Feedback and Trigger Mechanisms for Natural Disasters." Within the subproject A2, the main objectives are the coupling and the mass transfer between overlying and downgoing plate. We present a detailed seismic study of the near trench plate boundary, just 3 km landward of the Middle American Trench, located between the Quepos Plateau and the Cocos Ridge. In this area, previously recorded dip-profiles showed a very bright d\'{e}collement reflection of negative polarity within the first five kilometres landward of the trench. Along strike, the zero-offset reflection strength of the d\'{e}collement shows a high lateral variability. To further investigate these lateral variations, we deployed ten ocean-bottom-stations on a profile of 1.5 km length during the cruise 173 of RV Sonne in July 2003. Due to the shallow depth of the d\'{e}collement (around 700 m below seafloor), we are able to observe reflected waves at angles up to 50 degrees. This will enable us to describe the amplitude-variations with angle in detail and will allow us to further investigate the lithologic parameters causing this variations.
DE: 3025 Marine seismics (0935)
DE: 8150 Plate boundary--general (3040)
SC: Tectonophysics [T]
MN: 2003 Fall Meeting