Joint Interpretation of Multiple Passive Seismic Data Volumes

Geologic interpretation is best realized by joint interpretation of multiple geophysical techniques. After recording a 25 station, 7.5km linear passive array for over 48h, we divide the data into four time subsets characterized by total energy content. We investigate the 4 volumes with methods where the subsets satisfy the assumptions underlying the techniques. The first volume contains high total energy associated with anthropogenic noise. We analyze it with Rayleigh wave ellipticity velocity inversion. The second volume is 45s around a M5.9 teleseismic event. This data is analyzed for site amplification indications. The third subset has low energy content from 01:00 Sunday. This data is analyzed for departures from the background Rayleigh wave solution provided by volume 1. Fourth, 10-180s intervals are selected from the Sunday morning data and depth imaged with time-reversal algorithms. Finally, we interpret the results in an integrated framework. The first two volumes characterize the regional ambient wavefield, and indicates that the shallow subsurface is largely constant across the profile. The second two volumes indicate that there is observable body wave content providing local subsurface information from depth. 1D excess energy anomalies and 2D energy focusing are consistent with each other and an oil reservoir.