Sub-Project 1: Landslides monitoring and warning system

Landslides are one of the major causes of changes in landscape morphology for which reason the continous monitoring of the latter must be considered as mandatory for landslide hazard and risk assessment. Landslide monitoring and instrumentation can be performed at different levels and considering diverse set of parameters. The objectives of the Sub-Project are thus to (i) implement in-situ and remote monitoring techniques, (ii) use GIS for geodatabase or for data analysis and (iii) define alert thresholds through data analysis. The Sub-Project is coordinated by UNIMIB (Dept. of Geological Sciences and Geotechnologies) and features the participation of SGI-SW, UNEW, NTUA, SGI-MI, BRGM and SAA.

Disseminated material related to this Sub-Project can be found by clicking each of the links below:

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A summary of each of the tasks involved in this Sub-Project is provided below:

Task 1.1.1: In-situ and remote monitoring techniques

Sub-task 1.1.1.1: LIDAR for topographic or bathymetric mapping

In-situ and remote observations can help in this work. LIDAR (Light Detection and Ranging) is a technology that uses laser light for topographic or bathymetric mapping. The production of highly accurate topographic maps and multiple surveys through LIDAR could show the onset and occurrence of slow mass movements, the volume of displaced mass during fast mass movements, the main morphological features controlling the movement or characterising it. Furthermore, accurate topography could result very useful in the description of micro-topography and then in the understanding and modelling of water runoff and erosion.

LIDAR is used in this project to study landslides in clay and till slopes. A complete understanding of the advantages of LIDAR in slope stability investigations and monitoring has never been performed and this project could be a starting point for at least some geological and geomorphological settings.

Nevertheless, LIDAR is still quite expensive and its use can be prohibitive for small administrations. The aim of the project is also to investigate the cost-benefit issues regarding the use of LIDAR technology for landslide zonation and mapping. The same is true for other monitoring instrumentation and for GPS stations in particular.

Sub-task 1.1.1.2: Low cost GPS stations for in-situ monitoring

A low cost GPS station will be developed that could be deployed in greater networks or greater densities. This GPS stations will be tested on some landslides where in-situ monitoring networks already exist. Quality of GPS data will be assessed with respect to other GPS fixed stations already located within the test site areas. The aim is to develop a new low cost technology of GPS stations which will allow dense monitoring  which is of paramount importance for landslide mapping. It also acts towards the prediction of models and the improvement of landslides alert systems and the development of efficient strategies and policy.

Sub-task 1.1.1.3: Monitoring shallow slope failures

Monitoring becomes more difficult when coping with shallow slope failures which involve only colluvial and debris cover. This subject will be investigated in the project. Because of the variety of morphological conditions usually observed in coincidence of such slope failures, and of their abundance in alpine and pre-alpine areas, classical morphological and displacement oriented monitoring techniques don’t seem applicable. Monitoring of the pore pressure status, and its changes within the debris and colluvial cover, and rainfall pattern and intensity become much more relevant. These parameters allow the definition of triggering conditions and the calibration and validation of slope stability models.

Spatially distributed models will be implemented in the project, through GIS tools, in which hydrological models are coupled with slope stability models (e.g. infinite slope). This approach will allow to find more unstable areas and eventually to define some deterministic rainfall thresholds which will correlate probability of occurrence and possible surface of unstable areas. To accomplish this aim a pilot landslide inventory map at a regional scale (Central Italian Alps, 600km^2) will be produced starting from historical data and aerial photos. This geodatabase will allow also the preparation of landslide hazard maps by applying multivariate statistical techniques (SP2, Task 1.2.1).