GIS-based Calibration of MassMov2D

MassMov2D is a numerical model for simulating runout and deposition of landslide phenomena over a complex topography that is implemented in the free GIS PCRaster. This research aims at improving the mechanism of MassMov2D calibration and verifying its capability of representing complex landslides. In this paper the authors present the enhancement of the MassMov2D code due to the introduction of the Nash-Sutcliffe coefficient for model efficiency calculation; this enables the replacement of the inefficient 'trial and error' approach used for sensitivity analysis and calibration with a semi-automatic procedure. During this research the improved code was tested in a case study located on the Canaria Valley (Switzerland) where a complex landslide occurred. An optimal set of parameters were calculated for evaluating the effects of a possible further slope failure. The availability of a unique dataset of high resolution digital elevation models just before and after the collapse allows to precisely evaluate the sensitivity analysis and calibration of the model with the new procedure. The results demonstrate that this model is capable of reproducing the observed deposits even though some model limitations were identified in steep slope areas. Finally the study presents the expected scenario due to future landslide.