Modelling shear waves in OBS data from the Voring Basin (northern Norway) by 2-D ray-tracing
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文摘
Three component recordings from an array of five ocean bottom seismographs in the NW part of the Voring basin have been used to obtain a 2-D (S--wave) velocity-depth model. The S-wave modelling indicates that mode conversions occur at several high velocity interfaces (sills) in the 4-10 km depth range. An average ratio of 2.1 is inferred for the layers above the uppermost sill, indicative of both poorly consolidated sediments and a low sand/shale ratio. A significant decrease in the ratio (1.7) below the first sill may in part be attributed to well consolidated sediments, and to a change in lithology to more sandy sediments. An eastward thinning of the crystalline basement is supported by the shear-wave modelling.