2-D and 3-D modelling of wide-angle seismic data: an example from the V?ring volcanic passive margin

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• 作者：Stéphane Rouzo ; Frauke Klingelh?fer ; Hélène Jonquet-Kolst? ; Ridvan Karpuz ; Karl Kravik ; Rolf Mjelde ; Yoshio Murai ; Thomas Raum ; Hideki Shimamura and Paul Williamson ; et al.
• 关键词：Wide ; angle seismic ; Sub ; screen imaging ; 3 ; D modelling ; Gravity modelling
• 刊名：Marine Geophysical Researches
• 出版年：2006
• 出版时间：September, 2006
• 年：2006
• 卷：27
• 期：3
• 页码：181-199
• 全文大小：3,661 KB
• 刊物类别：Earth and Environmental Science
• 刊物主题：Earth sciences
  Oceanography
  Geophysics and Geodesy
  Geosciences
  Offshore Engineering
  
• 出版者：Springer Netherlands
• ISSN：1573-0581

文摘

This study presents the modelling of 2-D and 3-D wide-angle seismic data acquired on the complex, volcanic passive margin of the V?ring Plateau, off Norway. Three wide-angle seismic profiles were shot and recorded simultaneously by 21 Ocean Bottom Seismometers, yielding a comprehensive 3-D data set, in addition to the three in-line profiles. Coincident multi-channel seismic profiles are used to better constrain the modelling, but the Mesozoic and deeper structures are poorly imaged due to the presence of flood basalts and sills. Velocity modelling reveals an unexpectedly large 30 km basement high hidden below the flood basalt. When interpreted as a 2-D structure, this basement high produces a modelled gravity anomaly in disagreement with the observed gravity. However, both the gravity and the seismic data suggest that the structure varies in all three directions. The modelling of the entire 3-D set of travel times leads to a coherent velocity structure that confirms the basement high; it also shows that the abrupt transition to the slower Cretaceous basin coincides in position and orientation with the fault system forming the R?n Ridge. The positive gravity anomaly over the R?n Ridge originates from the focussed and coincident elevation of the high velocity lower crust and pre-Cretaceous basement. Although the Moho is not constrained by the seismic data, the gravity modelled from the 3-D velocity model shows a better fit along the profiles. This study illustrates the interest of a 3-D acquisition of wide-angle seismic over complex structures and the benefit of the subsequent integrated interpretation of the seismic and gravity data.