A multi-parameter monitoring system of a large French landslide : data, results and future perspectives
Résumé
Landslides are one of the major natural threats to human lives, settlements and infrastructure, causing enormous human suffering and property losses. Understanding the mechanisms influencing landslide dynamics is limited by the lack of dense and multi-parameter data. Nowadays landslide monitoring systems are more diffused and offer a temporary strategy to ensure public safety prior to definitive remediation or vulnerability-reducing works. They also provide accurate observation data enabling to improve the expertise and decision making. Since 2009, INERIS has been running a multi-parameter observations system placed along the West border of the very active zone of Séchilienne rockslide, where large cracks regularly open. This near real-time system is based on an integrated technological platform and combines in-depth microseismic, hydrogeological and geotechnical monitoring as well as meteorological and three-dimensional surface displacement measurements. The main time series obtained from this system includes the microseismic activity per day, the cumulative displacement and the daily rainfall. All these data are made available through INERIS cloud monitoring platform “e-cenaris” created. Indeed rainfall is one of the triggering factors of this landslide, but it is difficult to look for a relation between hydrology and kinematics in such complex geological conditions. The correlations between microseismic surges, acceleration phenomena of the surface and intense rainfalls have been visually and statistically analysed. However, it is not clear whether to define accurate qualitative similarities between such variables. Other studies are ongoing; in spite of data gaps and short-term monitoring, which complicate the study of this unstable slope.