The assessment of slope stability and the prediction of landslide evolution are difficult activities that require the identification of the variables involved and their careful and long-term monitoring.
Rainfalls are widely considered as the most important landslide triggering factor. They may control directly the landslide triggering or indirectly by means of fluctuation of groundwater levels.
Displacement can be obtained with different survey techniques.
Example of application to the Tessina landslide site
Here, we report the case of the Tessina landslide site (Belluno, Italy) for which displacement data were obtained from the analysis of image sequences and differentiated for different zones .
From displacement data of the different portions of the source area, it is possible to measure the probability cascade between movement events.
Also rainfalls are directly correlated to displacement.
From probabilistic analysis is possible to obtain many important information about the behaviour of the landslide. For example, for what concern the upper scarps (zone 1, 2, 3, 4), it was proved that the probability of movement is driven by combination of short rainfall duration, high maximum intensity and low mean intensity (i.e. scattered rainfalls) or the combination of long rainfall duration, high intensity and low maximum intensity (i.e., long and relatively uniform rainfall patterns). On the other hand, the persistency of movement depends more on the duration and intensity than on the maximum rainfall intensity; in other words, the total amount of rainfall is more important to the duration of movement than the peak rainfall.
Example of application to the Recoaro landslide site
A stereophtogrammetric technique was applied to assess the activity of the Recoaro landslide .
Gabrieli, F., Corain, L., & Vettore, L. (2016). A low-cost landslide displacement activity assessment from time-lapse photogrammetry and rainfall data: Application to the Tessina landslide site. Geomorphology, 269, 56–74. https://doi.org/10.1016/j.geomorph.2016.06.030
Brezzi, L., Gabrieli, F., Cola, S., Lorenzetti, G., Spiezia, N., Bisson, A., & Allegrini, M. (2020). Digital Terrestrial Stereo-Photogrammetry for Monitoring Landslide Displacements: A Case Study in Recoaro Terme (VI). In F. Calvetti, F. Cotecchia, A. Galli, & C. Jommi (Eds.), Geotechnical Research for Land Protection and Development (pp. 155–163). Springer International Publishing.