Multi-station inversion in array microtremor survey

摘要

Multi-station Inversion Method (MIM) is proposed and discussed for array microtremor survey in this paper. In inversion of phase velocities observed over a sedimentary basin, unlike the conventional method which inverts data for each site separately, the MIM inverts all the phase velocities simultaneously by using relationship equations of the unknown parameters among adjacent survey station (Array). Numerical tests of the algorithm show that the proposed method is more stable than the conventional single station inversion. Furthermore, traceability of a certain layer over a basin can be improved, because of similarity of shear-wave velocity profiles among adjacent survey stations. Another advantage of the MIM is that it can reduce the effects of random noise, thus improve the accuracy. The method was also tested using fields data. A comparion of shear-wave velocity structure given by MIM with existing PS log data shows a good agreement, confirming the effectiveness of this method.