<p>Landslide susceptibility is generally defined as the likelihood of a landslide occurring in a certain area on the basis of local terrain conditions. The aim of susceptibility assessment is to estimate the areas where landslides are likely to occur, based on the assumption that landslides will likely occur under the same conditions under which they occurred in the past.</p><p>The purpose of this study is assessing shallow landslide for Negrone and Tanarello catchments which are the upper basins of Tanaro river, a mountainous area within the Palaeo-European Continental Margin of the Alpine External Belt (External Briançonnais sucessions) and the Ligurian units of Maritime Alps of the Alpine Axial Belt (Pennidic Domain). The lithology is composed of silicate and to a minor extent carbonate rocks.</p><p>In the last decades, the study area has repeatedly been affected by slope instability events, mainly related to debris flows, characterized by extremely rapid movements. By integrating a detailed (1:5.000) geological and geomorphological field survey with ortophoto interpretation and existing information provided by Arpa Piemonte, landslide inventories have been produced. Only focusing on source areas, susceptibility assessment to debris flow have been performed by using a logistic regression approach, considering as covariates lithology, land use and morphometric factors derived from a digital elevation model (DEM) with a 5 m resolution. Source area pixel have been split into training and validation subsets by adopting a random partition. A certain number of pixels equal to the training set has been randomly extracted among stable cells, to prepare the dataset for logistic regression. The best set of covariates in controlling the spatial distribution of debris flows have been identified by iteratively adding one variable at a time and comparing the results. Susceptibility model fitting and prediction skill have been assessed based on validation subsets. The role of the considered factors in predisposing debris flow failures has been evaluated, discussing differences in the outcomes.</p>

<p>Drainage network systems are one of the more responsive elements to recent active tectonic from among all the topographic features. Their anomalies can be significant in areas with high relief energy or less noticeable where intense deposition rates might make capable tectonic signatures not visible. In addition, surface processes are even dominated by changes in climate. Since landscape evolution is the result of the combination of these elements, drainage network systems represent a key element for understanding the role and importance of different factors involved in the processes during Quaternary that have led to the formation of the current relief.</p> <p>The study area comprises two different zones in Piedmont region (North-Western Italy): the Western Po Plain and the Langhe and Monferrato hills, both located in a complex tectonic framework at which a juxtaposition on a crustal scale between Alpine metamorphic Units and the Ligurian Units of the Apennines takes place. A multi-disciplinary approach is proposed combining geomorphology and geostatistics, with the aim of obtaining a better understanding and knowledge of various aspects of the Quaternary evolution of the area on a regional scale.</p> <p>A morphometric analysis was carried out based on 5 m resolution DEM supported by geological and geomorphological field surveys. To assess the changes in the river network’s direction a quantitative geomorphic analysis of river pattern has been performed through Geographic Information System (GIS) and MATLAB® tools. Different parameters were calculated with the aim of detecting anomalies and the estimation of local uplift and different erosion rates.  Following the extraction of longitudinal river profiles, calculating Normalized Channel steepness index (K<sub>sn</sub>) has been possible for assessing river incision, based on local channel slope, contributing drainage area and some other characteristics related to incision processes and basin hydrology. This step has also allowed the identification of knickpoints whose presence represent a deviation of steady-state streams condition and hence a transient phase of potentially landscape changes.  These anomalies are present whether they were produced by tectonic deformation or by different factors. In addition, a paleotopographic reconstructions of Pleistocene deposits have allowed the estimation of the thickness of the deposits and the reconstruction of the river patterns during this period.</p> <p>Preliminary results have provided relevant evidence of potentially recent and important changes in the regional drainage network of Western Po Plain resulting from the combination of tectonic activity during the Early Pleistocene and the climatic variation from the Middle and Late Pleistocene.</p>

<p>On large landslide areas, two-dimensional and three-dimensional geological-technical models realization require a large number of subsurface data.</p> <p>We investigate a complex landslide system located in San Vito Romano, Central Italy, 40 km east from Rome where a large number of boreholes, piezometers and geophysical surveys are available.  </p> <p>The purpose of this work is the San Vito Romano landslide characterization in order to create a simplified graphic 3D model and to support a monitoring plan. The aim is also to support local authorities in civil protection activities.</p> <p>The geological context is characterised by a Tortonian sequence of turbidite deposits, characterised by marls and arenaceous intercalations, forming a monocline with 15-20° dip-direction eastward, parallel to slope inclination. Moreover, a complex hydrogeological system characterises the groundwaters.</p> <p>This landslide has a spatial extent of about 0.5 km<sup>2</sup> and it has been studied for lot of years. It affects San Vito Romano’s new town (built from the 60s) and it has been interpreted as a large rock translational slide. From a geomorphological point of view the village is located along a cuesta. Human activities consist in buildings, roads and public services, built over the years, even in the recent past.</p> <p>A multitude of technical reports were carried out in this area during the last decades: geological surveys for building projects, geotechnical surveys for landslide monitoring planning, academic studies and field survey to understand the geomorphological slope evolution, hydrogeological and geophysical survey.</p> <p>All the available surveys were censored in order to create a large database in GIS environment. The database containing all the information from 80 linear and punctual surveys.</p> <p>Therefore, a boreholes surveyed quick interpretation was carried out. First, the stratigraphy was simplified into three different lithological units: loose material belonging to the landslide, bedrock involved in the gravitational process and bedrock in place. The stratigraphic and geotechnical data were implemented by the seismic data.</p> <p>A Digital Terranean Model was created using contour lines and elevation points from a 1:2000 scale local topographic map.</p> <p>All available data has been entered into AutoCAD Map 3D and georeferenced in GIS environment. 7 E-W and 8 S-N cross sections were realized allowing a first two-dimensional landslide system interpretation. Finally, the cross sections were correlated to create a single simplified three-dimensional subsurface model.</p> <p>This model shows at least three surfaces of rupture at different depth and the geological setting of the wide translation slide. Moreover, it could be implemented with new data and it could be imported into slope stability and hydrogeological modelling software for numerical analysis.</p>

<p>In recent years, digital mapping systems have gained interest among geomorphologists thanks to the fast evolution of technology. However, a mapmaker still uses traditional cartographic supports as printed topographic maps, which need to be   subsequently digitalized. Every step adds an additional level of cartographic error, often difficult to quantify. A solution can be to map the landforms directly in digital format during the fieldwork through an ad hoc system.</p><p>With the purpose of making a “native” numerical cartography, GOGIRA (Ground Operative-system for GIS Input Row-data Acquisition) has been realized. GOGIRA consists of a set of hardware and software tools to digitalize real-world geomorphological elements and obtain georeferenced shapefiles. It is currently composed by two devices for data acquisition: an Android App for data collection and a Python-based software for coordinate computation. The technologies have been chosen to be enough accurate but cheaper than already available topographic tools. Each device uses an “Arduino Nano” board and low expensive sensors like MPU6000 (3 axis accelerometer + 3 axis gyroscope) or BNO055 (3 axis accelerometer + 3 axis gyroscope + 3 axis magnetometer).</p><p>GOGIRA has been tested in Aosta and Tanaro Valley, in North-Western Alps of Piedmont Region (Italy). The first case study was chosen in the context of the active monitoring of a complex landslide system close to an important highway that connects Italy, France and Swiss. It was possible to remotely (distance from 0.5 to 2.7 km from targets) map an area of limited access due to steep slopes, high scarps and rockfall hazard. Small single elements were mapped, as rockfall scarps not detectable from topographic support. The time for the survey has revealed to be short (a couple of hours included the search of a good observation point). The second case study was picked during the preliminary fieldwork for the realization of rolling tanks to mitigate the hydrologic hazard in the anthropized Tanaro Plain. The area has been investigated both with traditional methods and GOGIRA system, if morphometry allowed. Scarps, karst springs and debris/rock flow tracks were mapped.</p><p>The results obtained from both the tests highlight complications in mapping polygonal elements regarding visibility and overlaying but show a particularly high reliability in collecting data on linear and punctual geomorphic elements.</p>

<p>The geomorphological and geotechnical assessment of a large landslide should be always carried out to plan the best solution for monitoring and risk mitigation works. Too many times monitoring and works were realised following standard procedures without preventively comprehending the morphoevolution of the landslide system. This work aims to offer a full and multidisciplinary analysis in an anthropized area to supply strategic support for civil protection activities, to deepen the local natural hazard and try to reduce them.</p><p>We investigate a complex landslide system located in San Vito Romano, Central Italy, 40 km east from Rome. It has a spatial extent of about 1 km<sup>2</sup>. The geological context is characterised by a Tortonian sequence of turbidite deposits, characterised by marls and arenaceous intercalations, forming a monocline with 15-20° dip-direction eastward, parallel to slope inclination. Moreover, a complex hydrogeological system characterises the groundwaters.</p><p>A field survey has been carried out to recognize the geomorphological features and elements as crowns, scarps, tension cracks and all other geomorphic evidence. The survey also focused on building damages. A geomorphological-technical model has been realised interpreting boreholes, piezometers, inclinometers, high precision GPS stations and cracks digital metres, geotechnical and geophysical investigations, coupled with detailed digital elevation models analysis through GIS software. In this way the San Vito Romano landslide has been interpreted as a large rock translational slide in the upper part of the slope turning into a rotational slide in its accumulation zone. Data have been used for experimental slope stability analysis to find the main critical areas of the slope and correlate water table changes and landslide movements. Even though data model is still developing and calibrating, preliminary data provide realistic results. The individuation and characterization of most critical areas allow to plan where locate further instrumentations choosing the most appropriate ones for the two different detected portions of the landslide. Based on it, the suggested work consists in a drainage trench system upstream the main scarp to canalize the surface running waters avoiding infiltration in recharging area, and a large drainage borehole, for the purpose of limiting the water table changes downstream in the accumulation zone.</p>