Two-dimensional Born-type velocity inversion using multiple-frequency information

Author(s):  
A.G. Tijhuis ◽  
F.E. van Vliet
Geophysics ◽  
1987 ◽  
Vol 52 (1) ◽  
pp. 37-50 ◽  
Author(s):  
Tianfei Zhu ◽  
Larry D. Brown

A traveltime inversion scheme has been developed to estimate velocity and interface geometries of two‐dimensional media from deep reflection data. The velocity structure is represented by finite elements, and the inversion is formulated as an iterative, constrained, linear least‐squares problem which can be solved by either the singular value truncation method or the Levenberg‐Marquardt method. The damping factor of the Levenberg‐Marquardt method is chosen by the model‐trust region approach. The traveltimes and derivative matrix required to solve the least‐squares problem are computed by ray tracing. To aid seismic interpretation, we also include in the inversion scheme a fast algorithm based on asymptotic ray theory for calculating synthetic seismograms from the derived velocity model. Numerical tests indicate that the inversion scheme is effective, and that the accuracy of inversion results depends upon both noise in the data and the aperture of recording used in data acquisition. Two real examples demonstrate that the new inversion scheme produces velocity models fitting the data better than those estimated by other approaches.


2019 ◽  
Vol 205 ◽  
pp. 03015
Author(s):  
K. Allison Thomas

We describe methods using frequency combs and cavities for recording two-dimensional ultrafast spectroscopy signals with high sensitivity. By coupling multiple frequency combs to modes of an optical resonator, cavity-enhanced 2D spectroscopy signals are naturally generated.


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