Multiple attenuation in crustal-scale imaging: examples from the TAIGER marine reflection data set
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During summer of 2009, multi-channel marine seismic reflection data and wide-angle refraction data were acquired as part of the joint NSF and Taiwanese-funded TAIGER program with the goal of understanding the dynamics of arc-continent collision in Taiwan. One of the principle difficulties of crustal-scale imaging with marine reflection data such as these is the prevalent multiple contamination that obscures many of the deep crustal targets. Without effective treatment of multiples, many of the objectives of the TAIGER active source program may not be achieved. We present three profiles, one from each acquisition leg, that demonstrate the effectiveness of 2D surface-related multiple elimination (SRME) and radon filtering in attenuating much of this unwanted energy in broad ranges of water depths, seafloor topographies and lithologies. Two profiles from south of Taiwan image 3–4 km of sedimentary strata overlying moderately extended continental crust along the Eurasia continental shelf and a 5–6 km thick sedimentary section overlying thin crust consisting of faulted blocks and volcanic bodies along the continental slope. Our multiple attenuation efforts also reveal a seaward-dipping normal fault that penetrates into the upper mantle and separates thick crust of the continental shelf from thin crust of the continental slope. A profile from east of Taiwan reveals thin ocean crust of the Philippine Sea plate subducting beneath the Ryukyu trench that may be traced beneath the accretionary prism and Ryukyu forearc. These profiles demonstrate the success of our imaging strategy in the range of imaging environments spanned by the TAIGER marine reflection seismic data.
KeywordsContinental margin Subduction zone Crustal structure Marine geophysics Taiwan
The results of this paper would not be possible without the superior facilities of the R/V Marcus G. Langseth, and the hard work of the captain, crew and science staff. We would like to thank the many Taiwanese researchers and students involved in the TAIGER project, including (but not limited to), Dr. Chao-Shing Lee, Dr. Shu-Kun Hsu, Dr. T.K. Wang, and Dr. Char-Shine Liu, who also provided many useful suggestions in the preparation of this manuscript. We would also like to thank the three anonymous reviewers for their insightful feedback. Data were processed with Paradigm’s Focus and Geodepth software. Figures were made using Focus and GMT. This research was made possible through the NSF Continental Dynamics program (Grant EAR-0408609) and support from Taiwan’s National Science Council, Central Geologic Survey, and Ministry of Interior. University of Texas Institute for Geophysics contribution #2462.
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