The Sorrentina Peninsula is a densely populated area with high touristic impact. It is located in a morphologically complex zone of Southern Italy frequently affected by dangerous and calamitous landslides. This work contributes to the prevention of such natural disasters by applying a GIS-based interdisciplinary approach aimed to map the areas more potentially prone to trigger slope instability phenomena. We have developed the Landslide Susceptibility Index (LSI) combining five weighted and ranked susceptibility parameters on a GIS platform. These parameters are recognized in the literature as the main predisposing factors for triggering landslides. This work combines analyses conducted on Remote Sensing, Geo-Lithology and Morphometry data and it is organized in the following logical steps: i) Multi-temporal InSAR technique was applied to Envisat-ASAR (2003–2010) and COSMO-SkyMed (2013–2015) datasets to obtain the ground displacement time series and the relative mean ground velocity maps. InSAR allowed the detection of the areas that are subjected to ground deformation and the main affected municipalities; ii) Such deformation areas were investigated through airborne photo interpretation to identify the presence of geomorphological peculiarities connected to potential slope instability. Subsequently, some of these peculiarities were checked on the field; iii) In these deformation areas the susceptibility parameters were mapped in the entire territory of Amalfi and Conca dei Marini and then investigated with a multivariate analysis to derive the classes and the respective weights used in the LSI calculation. The resulting LSI map classifies the two municipalities with high spatial resolution (2m) according to five classes of instability. The map highlights that the high/very high susceptibility zones cover 6% of the investigated territory and correspond to potential landslide source areas characterized by 25°-70° slope angles. A spatial analysis between the map of the historical landslides and the areas classified according to susceptibility allowed testing of the reliability of the LSI Index, resulting in 85% prediction accuracy.

The identification of the mechanisms responsible for the deformation of calderas is of primary importance for our understanding of the dynamics of magmatic systems and the evaluation of volcanic hazards. We analyze twenty years (1997–2018) of geodetic measurements on Ischia Island (Italy), which include the Mt. Epomeo resurgent block, and is affected by hydrothermal manifestations and shallow seismicity. The data from the GPS Network and the leveling route show a constant subsidence with values up to −15 ± 2.0 mm/yr and a centripetal displacement rate with the largest deformations on the southern flank of Mt. Epomeo. The joint inversion of GPS and levelling data is consistent with a 4 km deep source deflating by degassing and magma cooling below the southern flank of Mt. Epomeo. The depth of the source is supported by independent geophysical data. The Ischia deformation field is not related to the instability of the resurgent block or extensive gravity or tectonic processes. The seismicity reflects the dynamics of the shallow hydrothermal system being neither temporally nor spatially related to the deflation.

This paper concerns the displacement field of the central-western part of the Mediterranean basin estimated by the analysis of three repeated GPS surveys (1995, 1996 and 1997) consisting of 8 sites of a network. This network includes for the first time the stations of Algiers and Arzew, located in Northern Algeria, an area not yet investigated by regional GPS surveys. Lampedusa station is located in the Sicily Straits rifting area while the other five stations of Cagliari, Wettzell, Madrid, Matera and Noto belong to the IGS permanent tracking network. The statistical analysis of 1995, 1996 and 1997 data show significant displacements at five stations. The displacement vectors of the African sites show a convergence between the African and the Eurasian plates at a rate of 0.8 ± 0.4 cm within a two year time span. A comparison between the displacements estimated in the present work and the ITRF96 determinations for the five permanent stations allow us to evaluate the motion of Lampedusa, Algiers and Arzew in the IERS Terrestrial Reference System.

Colli Albani Hills, a volcanic complex located 20 km SE of Roma (Italy), represents a long-dormant caldera system and its last eruption is dated back ~ 20 ky. It is subjected to seismic swarms, gaseous emissions and ground deformations. The whole volcanic complex is affected by landslides of different typologies and in the past the most frequent were debris flows. In this study, for the first time, the debris flows susceptibility of the complex is mapped through a heuristic approach that combines parameters recognized in literature as the main predisposing factors to slope instability. Such parameters are morphometry elements, lithology and land cover. The resulting map, validated through historical landslides, classifies the entire complex according to five degrees of susceptibility, identifying Tuscolano-Artemisio caldera edge, Mt. Faete, and steep slopes of Nemi and Albano lakes at high and very high susceptibility. The instability of the entire complex is further investigated measuring the ground deformations observed by using InSAR data in the period 2016–2023. InSAR results, validated through GNSS data, show the overall stability of the complex, except a few areas. In detail, an ongoing uplift of about 1.5 mm/yr is recorded in Genzano di Roma municipality. The InSAR results combined with the debris flows susceptibility map and historical landslides highlight the steep slopes of Albano and Nemi lakes and Giulianello locality, outside the caldera, as the areas potentially most predisposed to trigger debris flows as classified at very high susceptibility and affected by both ground deformations and historical debris flows.