Sedimentary basins investigation using teleseismic P-wave time delays
N.P. Agostinetti and F. Martini
Journal name: Geophysical Prospecting
Issue: Vol 67, No 6, July 2019 pp. 1676 - 1685
Info: Article, PDF ( 4.18Mb )
Passive seismic methods have been proven successful in recent years at retrieving information about the large-scale structure of a sedimentary basin. These methods are based on ambient noise recordings, and local and distant (teleseismic) earth-quake data. In particular, it has been previously observed that the arrival time of teleseismic P-waves recorded inside a sedimentary basin shows time delays and po-larization that both strongly depend on the basin properties and structure. In this paper, we present a new methodology for determining seismic P-wave velocity in a sedimentary basin, based on the time delay of a teleseismic P-wave travelling through the low-velocity basin infill, with respect to a teleseismic wave recorded outside the basin. The new methodology is developed in a Bayesian framework and, thus, it includes estimates of the uncertainties of the P-wave velocities. For this study, we exploit synchronous recordings of teleseismic P-wave arrivals at a dense linear array of broadband seismic stations, using data from two teleseismic events coming from two different incoming angles. The results obtained by the new proposed methodol-ogy are successfully compared to classical cross-correlation measurements, and are used to infer properties of a sedimentary basin, such as the basin bounding fault’s geometry and the average P-wave velocity of the sedimentary basin fill.