Preliminary results of the CRISP 3D seismic experiment, offshore Costa Rica

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Author(s): Bangs, Nathan L.; McIntosh, Kirk D.; Silver, E. A.; Ranero, C. R.; Kluesner, J. W.; von Huene, R.; Cavanaugh, S.; Graf, S.; Cameselle, Alejandra Lago; Baracco, Agnese M.; Nuñez, E.
Author Affiliation(s): Primary:
University of Texas at Austin, J. J. Pickle Research Campus, Austin, TX, United States
University of California, Santa Cruz, United States
Instituto de Ciencias del Mar, Spain
University of California, Davis, United States
National University of Costa Rica, Costa Rica
Volume Title: AGU 2011 fall meeting
Source: American Geophysical Union Fall Meeting, Vol.2011; American Geophysical Union 2011 fall meeting, San Francisco, CA, Dec. 5-9, 2011. Publisher: American Geophysical Union, Washington, DC, United States
Note: In English
Summary: In April and May of 2011, we acquired a new 3D seismic reflection data volume offshore Costa Rica, northwest of the Osa Peninsula. The goal of the survey was to examine the crustal structure and deformation history of this collision zone, and to clearly image the plate-boundary fault from the trench and into the seismogenic zone. These data will also help locate a deep site for riser drilling as part of the CRISP drilling program. The 3D survey covered 55 km across the upper shelf and slope, and into the trench. It extended 11 km along strike for a total survey area of 11 × 55 km. These data were acquired with the R/V Langseth using a 3300 cubic inch source shot every 50 m. We recorded the data on four 6-km-long, 468-channel streamers with 150 m separation. We have preliminary results from processing 2D seismic lines extracted from the 3D volume, and from initial 3D volume processing. In the preliminary images we can trace strong seismic reflections from the plate-boundary fault down to 3 s two-way travel time (approx. 5 km depth) below the seafloor and 26 km landward from the trench. The plate-boundary fault reflection amplitudes decrease substantially with depth and are difficult to depict on these preliminary profiles. The upper plate structure shows numerous faults, many extending down to the plate-interface, and intense folding and faulting of the slope cover sequences. Currently these data are being processed by the Spanish oil company, Repsol, and should reveal far more detail with complete 3D processing.
Year of Publication: 2011
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 07 Marine Geology and Oceanography; 20 Geophysics, Applied; Central America; Continental shelf; Continental slope; Costa Rica; Costa Rica Seismogenesis Project; Drilling; Faults; Geophysical methods; Integrated Ocean Drilling Program; Marine methods; Ocean floors; Offshore; Osa Peninsula; Programs; Reflection methods; Seismic methods; Streamers; Three-dimensional models; Two-dimensional models
Record ID: 2015099570
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data supplied by, and/or abstract, Copyright, American Geophysical Union, Washington, DC, United States

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