Microgravity corrections of underground and aboveground anthropogenic structures using portable laser scanning in urban areas
Abstract
Microgravity surveying is a widely used geophysical method to detect underground voids and cavities. Detecting underground cavities is instrumental to a wide array of applications: for example for collapse hazard mitigation in urban planning and in construction, or in archeological studies to find crypts. In urban settings, the influence of buildings and known underground structures result in strong negative gravity anomalies that may mask the target signal, and needs to be corrected for (Jacob et al. 2020). With the appropriate corrections, microgravity surveying is therefore applicable in dense urban city centers, with a significance and reliability that are closely linked to that of the applied corrections. In order to achieve the most reliable and accurate corrections, the precise 3D geometry of the corrected structures must be determined, which may be obtained by photogrammetry (Panisova et al. 2012), or by laser scanning devices. Hand-held portable laser scanning devices allow quick and easy point cloud generation, with cm-level accuracy (Dewez et al. 2017).
In this study, we test and benchmark different gravity correction schemes for both underground structures and complex historical buildings, using point clouds generated with hand-held portable laser scanning devices, on two case studies.
Domains
Geophysics [physics.geo-ph]
Origin : Files produced by the author(s)