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Simultaneous Inversion of Shear Wave Velocity and Layer Thickness by Surface-Wave Dispersion Curves
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 81st EAGE Conference and Exhibition 2019, Jun 2019, Volume 2019, p.1 - 5
Abstract
Summary
The surface-wave modal inversion is generally the final step in various surface-wave exploration methods. The most widely used inversion strategies are the iterative-linear methods, which usually only invert S-wave velocities while keep other parameters, including the thickness of each layer, as known a priori. Though easy implementation and fast computation, these strategies make the establishment of an appropriate initial model a time-consuming process, especially when other priori information is unavailable. We propose an inversion strategy that simultaneously inverts S-wave velocity and layer thickness, within the frame of iterative-linearization. To enhance the stability of this inversion strategy, we have made a comprehensive application of a logarithmic transform and the smoothness constraint on model. Additionally, the elements of the Jacobian matrix are calculated by an analytical method combining the Implicit Function Theorem and the reduced delta matrix. A synthetic example and a field data demonstrate that the proposed strategy has a comparable computation efficiency and stability as the traditional Vs-only iterative-linear inversion methods, and meanwhile, makes the building of initial model more straightforward. This inversion strategy can be used alone or be used jointly with the traditional schemes to considerably facilitate the building of initial model for surface-wave exploration methods.
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