“…Crosshole tomography has been used in mining exploration (Wong, 2000), aquifer delineation and hydrology-related topics (Hubbard and Rubin, 2000;Daley et al, 2004;Dietrich and Tronicke, 2009;Linder et al, 2010;von Ketelhodt et al, 2018), for characterising a host rock and its small-scale structures such as fault planes (Maurer and Green, 1997;Rumpf and Tronicke, 2014;Schmelzbach et al, 2016;Doetsch et al, 2020;Shakas et al, 2020), for investigating pore pressure variations in aquifers and caprocks (Daley et al, 2008;Marchesini et al, 2017;Grab et al, 2022) and voids in karst regions (Duan et al, 2017;Kulich and Bleibinhaus, 2020;Peng et al, 2021). Furthermore, Gusmeroli et al (2010) and Axtell et al (2016) used GPR-based travel time tomography to estimate the water content in a polythermal glacier.…”