Geophysical surveys for the investigation and monitoring of landslide areas

During recent years several large landslide hazards took place in Austria. One of the largest happened at Sibratsgfäll, where about 70 million m3 and an area of 1,4 km2 was involved in a hazardous mass movement, that disturbed 13 buildings completely. Starting on the 19.May 1999 after three days of heavy rainfall, the whole area of Rindberg started to move with a maximum speed of 10m/day. Immediately after this event, a multi-disciplinary research program was started to investigate the structure and triggering cause of this landslide and to develop a geoelectrical monitoring system to register pre-alarm critical values. The research program included: • GPS measurements to monitor actual movements • Airborne geophysical measurements involving measurement of electromagnetic field, gamma ray, magnetics, infra red temperature and soil humidity • Detailed geological and hydrological mapping • Ground geoelectrical surveys on selected lines • Development of a geoelectrical monitoring system, with additional hydrological and meteorological monitoring parameters for calibration purposes Within this talk result of the structural investigations, focusing on the geophysical work, as well as the first results from a new geoelectrical monitoring network will be presented.