Imaging and Locating Buried Tunnels Using a High-Resolution S-wave Seismic Survey

Abstract

Knowing the location and characteristics of shallow subsurface structures like tunnels, cavities, archeological ruins, etc. is of importance for different disciplines and application. To image and/or characterize such objects of interest, different geophysical methods are used. For imaging of a very shallow network of tunnels, the high-resolution seismic method with active sources provide valuable information. We show the results of analysis of an S-wave profile recorded over a network of very shallow tunnels in the Netherlands. The survey used a high-frequency vibratory S-wave source and horizontal particle-velocity geophones, both oriented in the crossline direction, along three lines. We process the reflection data along one of the lines to obtain a stacked section in depth. We also use a method inspired by seismic interferometry to localize a scatterer along the line. We show that both techniques image well the subsurface structures taking into account the 3D ambiguity of processing 2D data.