Multi-Sensor Geophysical Measurements in a Simulated, Lab-Scaled Urban Environment.

Adapting urban areas to the current demands of the energy transition, as well as maintaining crucial infrastructures like roads, bridges and quay walls, requires large investments for which understanding of the subsurface is vital. In this study, an urban environment was created in a scaled lab environment to test a multi-sensor geophysical setup. The lab setup included a brick top layer, different soil types and buried, leaking pipelines. Co-located electrical resistivity, seismic and ground radar measurements were conducted while varying the hydrological conditions as well as simulating a leakage from a pipeline. Where the ground radar data most clearly delineated boundaries between different elements in the subsurface, the electrical resistivity and refraction tomography provided material parameters, though detection of small features like pipelines was not possible. The leakage of the pipeline was clearly detected by monitoring the electrical resistivity and, to a lesser extent through reflections of the leakage front in the ground radar data. The acquired data from this study is a good starting point for joint-inversion and data fusion, that is expected to yield more useful information about the sub-surface than each of the individual sensors by itself.