ABSTRACT Distributed acoustic sensing (DAS) is an emerging fiber-optic technology that offers cost-effective and widely accessible solutions for diverse applications, including those in urban environments. There are, however, limited case studies using DAS for small-scale civil engineering projects. The feasibility of using borehole DAS to characterize shallow subsurface properties was evaluated, and its integration with surface geophone data was explored. Investigations were conducted at a complex urban archaeological site using active and passive seismic methods. First, by combining first-arrival P-wave travel times extracted from active data recorded by borehole DAS and surface nodes, P-wave velocity models were reconstructed, and their relevance for subsurface characterization was evaluated. Second, passive and active data using DAS and surface nodes to extract Rayleigh wave dispersion curves were recorded, and S-wave velocity models were reconstructed. Third, the potential of interwell ambient noise interferometry using passive DAS data was demonstrated. Despite the specific challenges associated with the DAS technology and the need for an improved processing workflow, the results showed that DAS could be effectively applied to small-scale civil engineering problems using active and passive seismic sources. This is of particular interest given the growing use of fiber optics in urban environments. Additionally, ambient noise sources were shown to be effective in combination with DAS, eliminating the need for an active campaign, which, in certain situations, may be limited by authorization or logistical difficulties. Borehole DAS combined with surface geophones provides a feasible and flexible seismic acquisition approach in complex environments that could be suited for long-term monitoring.
Nesterova et al. (Mon,) studied this question.