Using overlapping sonobuoy data from the Ross Sea to construct a 2D deep crustal velocity model

• Published in: Marine Geophysical Research
• Main Authors: Selvans, M. M., Clayton, R. W., Stock, J. M., Granot, R.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Springer Verlag 2012
• Subjects: Sonobuoy; Multi-channel seismic; Ross Sea; Finite-difference; 2D velocity model; Crustal structure; Clayton; Adare; Adare Basin; Antarc*; Antarctica
• Online Access: https://doi.org/10.1007/s11001-011-9143-z

Sonobuoys provide an alternative to using long streamers while conducting multi-channel seismic (MCS) studies, in order to provide deeper velocity control. We present analysis and modeling techniques for interpreting the sonobuoy data and illustrate the method with ten overlapping sonobuoys collected in the Ross Sea, offshore from Antarctica. We demonstrate the importance of using the MCS data to correct for ocean currents and changes in ship navigation, which is required before using standard methods for obtaining a 1D velocity profile from each sonobuoy. We verify our 1D velocity models using acoustic finite-difference (FD) modeling and by performing depth migration on the data, and demonstrate the usefulness of FD modeling for tying interval velocities to the shallow crust imaged using MCS data. Finally, we show how overlapping sonobuoys along an MCS line can be used to construct a 2D velocity model of the crust. The velocity model reveals a thin crust (5.5 ± 0.4 km) at the boundary between the Adare and Northern Basins, and implies that the crustal structure of the Northern Basin may be more similar to that of the oceanic crust in the Adare Basin than to the stretched continental crust further south in the Ross Sea. © 2011 Springer Science+Business Media B.V. Received: 13 June 2011; Accepted: 1 December 2011; Published online: 20 December 2011. We would like to thank Captain Mike Watson, the crew, and the Raytheon Polar Services Corporation technical staff on board the Nathaniel B. Palmer. This study was supported by National Science Foundation grants OPP04-40959 (S. Cande) and OPP-0440923 and OPP-0944711 (J. Stock and R. Clayton).