Geophysical analysis of an area affected by subsurface dissolution – case study of an inland salt marsh in northern Thuringia, Germany

Abstract. The subsurface dissolution of soluble rocks can affect areas over a long period time and pose severe hazard. We show the benefits combined approach using P-wave SH-wave reflection seismics, electrical resistivity tomography, transient electromagnetics, gravimetry for better understanding process. study area, “Esperstedter Ried” in northern Thuringia, Germany, located south Kyffhäuser hills, is large inland salt marsh that developed due to at approximately 300 m depth. were able locate buried structures zones, faults fractures, potential fluid pathways, aquifers, aquitards based on seismic electromagnetic surveys. Further improvement model was accomplished by analyzing data indicates dissolution-induced mass movement, as shown local minima Bouguer anomaly Esperstedter Ried. Forward modeling data, combination with results, delivered cross section through from north south. conclude tectonic movements during Tertiary, which led uplift hills formation parallel perpendicular low mountain range, initial trigger dissolution. fractured Triassic lower Tertiary deposits serve pathways groundwater leach deep Permian Zechstein deposits, since erosional processes are more intense near faults. artesian-confined saltwater rises towards surface along fracture networks, it formed time. In past, formations several, now buried, sagging collapse structures, and, entire region affected recent sinkhole development, still ongoing. From results this study, we suggest geophysical investigation prone improve knowledge control factors, hazardous areas, thus processes.