Characterization of the 3D geometry of flow-like landslides: A methodology based on the integration of heterogeneous multi-source data

The geometry of the bedrock, internal layers and slip surfaces control the deformation pattern and the mechanisms of landslides. A challenge to progress in understanding landslide behavior is to construct accurate 3D geometrical models from different surveying techniques. The objective of this work is to present a methodology for integrating multi-source and multi-resolution data in a 3D geometrical model using geostatistical tools. The methodology consists in integrating the data by extracting relevant information on the internal structure of the landslide and in detecting possible incoherencies between different interpretations. A simple method to classify the input data and to control their influence on the model interpolation is proposed through the development of an expert reliability index. The methodology is applied for the creation of a 3D geometrical model of the Super-Sauze mudslide (South French Alps) for which an extensive dataset is available. Error calculation and expert geomorphological interpretation allow one to select the most suitable interpolation algorithm and to define the volumes of each layer. The proposed 3D geometrical model highlights the influence of the bedrock geometry on the observed kinematic pattern.