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| | Abstract | | In order to improve the depth image in accretionary sediments, we applied advanced technologies to 3D seismic data off Kumano in Nankai Trough. The 3D MCS survey was conducted in 2006 as a site survey for IODP Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE). The seismic data had several problems to degrade image quality, such as multiple reflections smearing the deep target signals and the cable feathering due to high-speed Kuroshio current. Technologies for data processing and depth imaging have been highly developed in a decade after the initial processing. The recent broadband processing with full deghosting could recover low frequency energy and improve the image quality with enhanced broadband signals. Multiple reflections and strong noise were better attenuated by applying advanced methods in combination. Non-uniform fold distribution due to the cable feathering could be regularized by means of the optimized 4D trace interpolation. Then, velocity model building (VMB) and pre-stack depth migration (PSDM) considering tilted transversely isotropic (TTI) anisotropy media were carried out. We obtained a new 3D depth image with high quality and high resolution. This result will contribute to understanding detail deformation structures in accretionary sediments. |
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