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Rayleigh wave propagation in shallow energy , the method is simple , high efficiency of field work , and thus the Rayleigh wave exploration method has been widely used in engineering geological exploration and engineering quality testing field . In practical work , the Rayleigh wave dispersion curve was \However, both the Rayleigh surface wave forward or inversion , as well as the extraction and application of the Rayleigh wave dispersion curve , there are many problems, such as : Rayleigh wave propagation and propagation mechanism ; Rayleigh wave dispersion curve \Forward inversion , inversion required forward . So , Rayleigh wave forward modeling is necessary. Rayleigh wave forward modeling have stayed in the level of the free-surface conditions numerical simulation of the Rayleigh wave , the actual engineering geological survey , the surface is often the ups and downs , and the surface wave propagation along the surface , the surface is inevitable , it is necessary to study the undulating surface Rayleigh wave propagation and propagation mechanism . The speed ( stress ) the time of the odd-order higher derivative converted to stress derivative (speed) of space , use of time and space differential accuracy can be up to any order of the higher - order finite difference method, using the staggered grid technology , order velocity - stress elastic wave equation is solved numerically . Deal with the ups and downs of the free boundary , so that it shear stress and parallel to the normal stress is equal to zero , without any special treatment when computing speed . In order to calculate the stress , the speed of the surface are set to zero. In order to verify the results of numerical simulation , special select several undulating surface model ( such as : two media , underground caves , weak interlayer ) forward modeling and analysis of the wave field characteristics . Overall, this gives the Rayleigh wave in the ups and downs interface finite difference method forward .
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