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SAR interferometry has proven capable of measuring surface displacements in various situations including ground-settlement, landslides and excavations. We present a case study that consists of a tunnel excavation under a slope where dormant deep seated landslides are recognized. We take advantage of the high resolution images of the COSMO SkyMed Satellite system, that has a high sampling frequency, to measure the distribution of displacements in space and time. Our results are compared to ground-based InSAR data, surface geophysical techniques, GPS and inclinometer measurements. The data were acquired between 2011 and 2015 during the construction phase of the highway that will connect Bologna with Florence across the Northern Apennines. The tunnel passes under the small villages of Ripoli and Santa Maria Maddalena. The geological conditions are characterized by highly sheared flysch sandstones that belong to the LigurianMonghidoro Formation, a unit that is well known for its poor geomechanical properties and high landslide susceptibility. The work on the tunnel started in 2011 and, with the advance of the tunnel front, severe surface displacements were induced, causing damage to houses and infrastructure. The deformation slowed down after the tunnel was completed in November 2014, and low displacement rates were registered during the spring of 2015. The data illustrate the evolution of ground deformations as the excavation proceeds. In particular the InSAR results obtained with the Stanford Method of Persistent Scatterers (StaMPS) for the X-Band data of COSMO SkyMed give interesting insights into the nature of observed surface deformations that include clear downslope movements. 55 SAR scenes were analyzed that had been acquired in ascending and descending orbits, between December 2012 and February 2015. Together with the new findings from combined HVSR-MASW techniques and a detailed remapping of the area, a new conceptual geological model of the slope is developed.

In many Italian regions and, in particular, in Emilia Romagna (RER), most land-use policies are based on Landslide Inventory Maps and on the landslide’s observed state of activity, that has riskily poor forecast significance. In this work we tried to realize a geomorphologic-heuristic model aiming at estimating the dormant landslides reactivation likelihood. The model is only focused on the spatial forecast as no correlation with rainfalls or return period are considered. Based on the typical reactivation process, three different landslide issues have been considered: (1) the shallow landslide initiation susceptibility in the areas upwards the mapped landslides (starting from the results of another model we developed in 2006); (2) the “push and undrained loading” effect of active landslides on the dormant accumulations, evaluated through a GIS-based geometric analysis; (3) The presence of documented past reactivations in the RER’s Historical Landslide Database. Combining these different topics we obtained a new classification of those landslides mapped as dormant, that can be very useful to overcome the actual planning practice forecast weaknesses.

Extensive landslide occurrences affected the Emilia-Romagna Region (north Apennines, Italy) during March–April 2013 due to a high-intensity precipitations and contemporaneous snow melting. During this period, incessant and intense precipitations characterized by a maximum height equal to 350 mm in the piedmont sector and 700 mm in the inner zones (up to fourfold the amount of predictable rainfalls) occurred. This event produced a relevant economic loss due to damages to several private properties and public infrastructures; in fact, local authorities advised about 1,500 damages. The landslide typologies occurred are generally earth slides and earth flows, even if some rock falls was also documented. Usually, landslides appeared as reactivation of preexisting movements and mainly involved the terrain belonging to the Ligurian Flysch Units, characterized by a stratigraphic succession of sandstones, marls and clays. Landslides advised by local authorities have been verified and successively included in the “Historical database of landslide events” of the Emilia-Romagna Region that presently records about 9,000 events, starting from 1,800 to present days. Major landslides was checked in the field and their geometry systematically updated in the already existing GIS-based “Landslide inventory map” of the Emilia-Romagna Region. The updated landslide data are relevant for immediate planning purposes and remediation strategies at both local and regional scale. They are also significant for subsequent susceptibility modeling and related hazard assessment.

Rapid assessment of landslide activity is important in case of adverse climatic conditions leading to civil protection’s alerts that require increased surveillance of risk areas. GB-InSAR is nowadays becoming a consolidated near-sensing monitoring technique for slope movements. It can be installed rapidly and it can rapidly provide results in the form of displacement maps. However, it has never been thoroughly tested in radar-hostile conditions such as these posed by large-scale earth slides – earth flows covered by a canopy of trees bushes and meadows, that are the typical landslides in Emilia Romagna Apennine. As sparse small villages, buildings, roads and other lifelines are often built on these landslide bodies, they are of particular concern for civil protection, especially during prolonged rainfall periods that determine attention/alerting conditions. To test the possibility to achieve improved surveillance capability in case of attention needed, a series of GB-InSAR spot campaigns lasting from a week to a month, was carried out in 2010–11 in several landslides of Emilia Romagna Apennine using a commercial interferometric radar. The aim was to evaluate the performance of the technique for rapid assessment of landslide activity, even in case of partly vegetated soil coverage conditions. The paper deals with the results obtained in 3 out of the 11 monitored sites.

The Emilia Romagna Region (RER) is probably one of the most landslide susceptible regions of the world, with ~24 % of the mountain sector covered by landslide accumulations. The regularly updated 1:10,000 Landslides Inventory Map (LIM), managed by the Regional Geological Survey, counts more than 70,000 landslides. Nowadays most land-use planning is based on LIM but this has several intrinsic shortcomings, mainly due to its scale and forecast significativity. This paper presents the methods we used to compile a detailed susceptibility map for the whole RER Apennines.

We monitored positive pore water pressure in a clay slope in the Apennines to investigate how rainfall influences the pore pressure distribution along the soil profile and, consequently, affects slope stability conditions. Data refers to the first season of monitoring activities (August 2001–June 2002). The study site is located at the head of a complex landslide, where incipient shallow failures are visible along the slope. The preliminary analysis of pressure data allowed to point out consistent trends, which manifested throughout 11 months. During the cold and wet season, saturation always extends close to the ground surface ( < 1 m) and pore water pressure measurements indicate a strong downward component of the flow, which is largely dominant over the downslope component, in any condition. Response to rainfalls at shallow depth (1 to 3 m) generally consists in a pressure pulse whose delay is relatively short if compared to low permeability of the soil and whose nature appears clearly transient. Although no failure occurred along the slope during the observation period, it is very likely such transient response would mimic the pore water pressure pattern capable to cause sliding. The presence of prefertial flow path in the sub-surface can only explain anomalous response of some sensors or substantial differences between buried at similar depths.