Sinkholes – collapse structures, of a few meters to several hundreds of meters in diameter, in their most spectacular form – pose a serious hazard for population and infrastructure, especially in urban regions. They are caused by leaching of soluble rocks in the subsurface (subrosion) and the associated creation of cavities or destabilisation of the rock.
The aim of the joint project SIMULTAN (Sinkhole instability: integrated multi-scale monitoring and analysis) is the characterisation and monitoring of sinkhole areas by means of geophysical, petrophysical and hydrogeological methods to develop an early warning system of instability. The studies are supported by scenario simulations and modelling. The focus areas of the research project SIMULTAN are Thuringia and Hamburg, where sinkholes or subsidence processes have been observed in urban regions. The LIAG is involved in the project with two working packages: the determination of key geophysical parameters for monitoring critical zones and the geodetic-gravimetric monitoring of sinkhole areas.
High-resolution shear wave seismics, borehole seismics (VSP) using P- and S-waves, and well logging methods are applied in order to investigate the subsurface structure and to identify geophysical parameters. The aim is to derive key geophysical parameters that are suited for the characterisation of critical zones. By means of repeated surveys, temporal changes of the physical parameters shall be determined.
The surface deformation is monitored by regular levelling measurements. The identification of potential mass movement in the subsurface that cause the surface deformation and sinkholes poses a huge challenge. We attempt to solve it by use of repeated high-precision gravimetric surveys and to verify it by modelling the mass deficits.
- KERSTEN, T., KOBE, M., TIMMEN, L., SCHÖN, S., GABRIEL, G. & VOGEL, D.;2016O; On Integrated Geodetic Monitoring for Sinkhole-Induced Surface Deformation and Mass Dislocation. - Ext. abstract, 3rd Joint International Symposium on Deformation Monitoring (JISDM), 30.-01.04.2016; Vienna.
- WADAS, S., POLOM, U., KRAWCZYK, C.M., 2016. High-resolution shear wave reflection seismics as tool to image near-surface subrosion structures – a case study in Bad Frankenhausen, Germany. Solid Earth
Helmholtz Centre Potsdam, German Research Centre for Geosciences (GFZ)
Freie Universität Berlin
GGL Geophysik und Geotechnik Leipzig GmbH
Helmholtz Centre for Environmental Research – UFZ
Gottfried Wilhelm Leibniz Universität Hannover
Technische Universität Berlin
Behörde für Stadtentwicklung und Umwelt Hamburg
Thüringer Landesanstalt für Umwelt und Geologie
Landesamt für Landwirtschaft, Umwelt und ländliche Räume Schleswig-Holstein