LIAG
 

Junior Research Group Subrosion

The most obvious surface expression of subrosion is a sinkhole (top left: near Bad Frankenhausen, Thuringia, Germany; bottom left: Innerste Mulde, Lower Saxony, Germany). In Bad Frankenhausen, e.g., the tilted tower demonstrates clearly that subrosion comprises far more than just sinkholes visible at surface. The tilt of the tower is due to subsurface leaching and void formation.

Subrosion, i.e., leaching of soluble rocks such as rock salt, anhydrite, gypsum and limestone mostly due to groundwater, is usually of natural origin but can additionally be enhanced by anthropogenic interferences. In recent years, public awareness of subrosion processes in terms of the in parts catastrophic implications and incidences increased. Especially the sinkholes in Schmalkalden and Tiefenort (Thuringia, Germany) are – based on the unforeseen collapse events and associated damage in 2010 – two dramatic examples. They illustrate that to date the present knowledge of those processes and therefore the predictability of such events is insufficient.

The complexity of the processes requires an integrated geophysical approach which investigates the coupling of structure, hydraulics, solution processes and mechanics and finally contributes to a better understanding of the processes by reliable imaging and characterization of subrosion structures.

Since mid 2014, the junior research group Subrosion of LIAG is inter-sectional engaged in geophysical investigation of subrosion processes. The focus of the junior research group is the application, enhancement and combination of various geophysical methods at the surface but also in boreholes. This includes monitoring of (surface) deformation and variation of gravity as well as seismic, geoelectric and electromagnetic methods. Petrophysical investigations (with focus on spectral induced polarisation – SIP) are conducted to characterise the processes on pore scale. Numerical studies are applied to advance the understanding of void forming processes and the mechanical consequences in the dynamic interaction. Those subtopics are strongly interconnected.

The following topics are the major focus of the junior research group:

Petrophysics

Surface Deformation

Electromagnetics

Seismics

Numerical Modelling