In recent years, physically-based numerical models have frequently been used in the framework of early-warning systems devoted to rainfall-induced landslide hazard monitoring and mitigation. For this ...reason, in this work we describe the potential of SLIP (Shallow Landslides Instability Prediction), a simplified physically-based model for the analysis of shallow landslide occurrence. In order to test the reliability of this model, a back analysis of recent landslide events occurred in the study area (located SW of Messina, northeastern Sicily, Italy) on October 1st, 2009 was performed. The simulation results have been compared with those obtained for the same event by using TRIGRS, another well-established model for shallow landslide prediction. Afterwards, a simulation over a 2-year span period has been performed for the same area, with the aim of evaluating the performance of SLIP as early warning tool. The results confirm the good predictive capability of the model, both in terms of spatial and temporal prediction of the instability phenomena. For this reason, we recommend an operating procedure for the real-time definition of shallow landslide triggering scenarios at the catchment scale, which is based on the use of SLIP calibrated through a specific multi-methodological approach.
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•Rainfall-induced shallow landslides cause human casualties and significant damage.•Numerical models are useful tools for the prediction of these phenomena.•SLIP model is able to predict the space-time evolution of shallow landslides.•SLIP is used within an operating procedure for the real-time prediction of landslides.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
2.
The Italian approach to seismic microzonation Moscatelli, Massimiliano; Albarello, Dario; Scarascia Mugnozza, Gabriele ...
Bulletin of earthquake engineering,
09/2020, Volume:
18, Issue:
12
Journal Article
Peer reviewed
Seismic microzonation represents a basic tool for local administrations in the developing of cost-effective risk reduction strategies and emergency planning. In recent years, the Italian scientific ...community has been deeply involved in implementing best-practices and tools to make seismic microzonation studies affordable by allowing its widespread application. Specific guidelines were provided that are representative of the international state of the art in this field. Moreover, the national Center for Seismic Microzonation and its applications (CentroMS) was established, which includes the most important Italian scientific institutions involved in seismic microzonation studies during last years. One of the purposes of this Center is supporting local Authorities and professionals in the field practice. Effectiveness of this organization has been tested during most recent seismic sequences, where the Center was charged to support the development of reconstruction plans. In this review paper the main features of these activities are addressed by focusing on experiences gained in the seismic microzonation studies carried out at 138 Municipalities in the area of Central Italy damaged by the 2016–2017 seismic sequence.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Ground deformation monitoring is a crucial task in geohazard management to ensure the safety of lives and infrastructure. Persistent scatterer interferometric synthetic aperture radar (PS-InSAR) is ...an advanced technique for measuring small displacements on the Earth’s surface. Estimated PS-InSAR time series acquired by Sentinel-1 satellites provide a great opportunity for effective monitoring of ground deformation in recent years. However, challenges arise when processing these time series due to their non-uniform sampling, noise from atmosphere and preprocessing issues including phase unwrapping and others. Therefore, estimating the location and direction of trend turning in such time series, as an indicator of ground deformation, is not an easy task. In this work, a sequential turning point detection method (STPD) is proposed and compared with other change point detection methods. Using a large set of simulated time series with various noise types, it is shown that STPD outperforms other methods in terms of overall accuracy and root mean square error for location and direction of trend turnings. As a case study, STPD is applied to detect turning points within PS-InSAR time series for the province of Frosinone in Italy and classified using topography and land cover/use. In addition, an area susceptible to landslides is selected to estimate the starting dates of potential slow-moving landslides. It is also shown that the turning points in the local precipitation time series have a high correlation with the ones in the PS-InSAR time series, indicating that precipitation is a major triggering factor of the displacements in the area. The STPD can rapidly and effectively detect locations and directions of trend turnings and is freely available online in both MATLAB and python.
•A robust trend turning point detection method is proposed, namely, STPD.•A normalized index is proposed to distinguish jumps from turning points in STPD.•The STPD can process one million time series of size 100 within an hour.•The STPD was successfully applied to PS-InSAR time series for Frosinone in Italy.•Most displacement turning points were correlated with precipitation turning points.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The aim of this work is to define reliable susceptibility models for shallow landslides using Logistic Regression and Random Forests multivariate statistical techniques. The study area, located in ...North-East Sicily, was hit on October 1st 2009 by a severe rainstorm (225mm of cumulative rainfall in 7h) which caused flash floods and more than 1000 landslides. Several small villages, such as Giampilieri, were hit with 31 fatalities, 6 missing persons and damage to buildings and transportation infrastructures. Landslides, mainly types such as earth and debris translational slides evolving into debris flows, were triggered on steep slopes and involved colluvium and regolith materials which cover the underlying metamorphic bedrock. The work has been carried out with the following steps: i) realization of a detailed event landslide inventory map through field surveys coupled with observation of high resolution aerial colour orthophoto; ii) identification of landslide source areas; iii) data preparation of landslide controlling factors and descriptive statistics based on a bivariate method (Frequency Ratio) to get an initial overview on existing relationships between causative factors and shallow landslide source areas; iv) choice of criteria for the selection and sizing of the mapping unit; v) implementation of 5 multivariate statistical susceptibility models based on Logistic Regression and Random Forests techniques and focused on landslide source areas; vi) evaluation of the influence of sample size and type of sampling on results and performance of the models; vii) evaluation of the predictive capabilities of the models using ROC curve, AUC and contingency tables; viii) comparison of model results and obtained susceptibility maps; and ix) analysis of temporal variation of landslide susceptibility related to input parameter changes. Models based on Logistic Regression and Random Forests have demonstrated excellent predictive capabilities. Land use and wildfire variables were found to have a strong control on the occurrence of very rapid shallow landslides.
•Multivariate statistical susceptibility models for very rapid shallow landslides•Sample size and type of sampling influence results and performance of models.•Logistic Regression and Random Forests proved excellent predictive capabilities.•Land use and wildfires have a strong control on rapid shallow landslide occurrence.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Viscoplastic behavior of jointed rock masses still represents a main research topic due to the reduced possibilities of carrying on long-term tests on site as well as to the reduced ...representativeness of laboratory samples if compared to the scale of the study-case. Rock masses are often involved in creep processes as in the case of gravity-induced deformations affecting relevant portions of natural slopes. These processes can interact with main infrastructures, among which dams, pipelines, aqueducts, tunnels, highways and railways.
This study is focused on laboratory tests performed to deduce the rheological behavior of a rock masses at a reduced scale for defining the influence of joint attitude and properties on viscoplasticity. A physics of reduction scaling of mechanical behavior (down-scaling) was preliminary applied to select the most adapt material for laboratory tests; the obtained results were then reported to the effective slope scale (up-scaling).
The tested specimens were realized by an artificial moisture whose mechanical properties were scaled respect to limestones outcropping in a mountain ridge involved in already documented gravity-induced slope deformation that caused an intense rock mass jointing.
Viscoplasticity was analyzed based on uniaxial compressive strength (UCS) and creep tests. The test results were then up-scaled according to an “equivalent continuum approach” and an equivalent viscosity for the outcropping rock mass was derived. The following performed up-scaling is representative for a creep process acting over a time interval of about 200 years.
The obtained viscosity values for the equivalent rock range from 4.23·1018 up to 1.56·1019 Pa∙s and are in good agreement with the values derived by back-analysis through stress-strain numerical modeling of the gravity-induced slope deformation involving Mt. Rocchetta. The obtained results demonstrate that properties of pervasive joints are not negligible on rock mass creep acting at slope scale which can drive gravity-induced processes toward paroxysmal failures.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Land cover and climate monitoring is a crucial task in agriculture, forestry, hazard management, and ecosystems assessment. In this paper, normalized difference vegetation index (NDVI), land surface ...temperature (LST), and land cover products by the moderate resolution imaging spectroradiometer (MODIS) as well as precipitation were utilized to monitor the spatiotemporal dynamics of vegetation and climate along with their correlation and coherency across Italy during 2000–2021. The analyses were performed on both pixel and ecoregion levels via the least-squares wavelet software (LSWAVE). It was found that relatively more areas in all ecoregions had positive NDVI gradients than negative for each month since 2000. It was estimated that the average NDVI has increased by ∼0.07 since 2000 for all ecoregions. Except the southern ecoregion which showed an insignificant daytime cooling, other ecoregions have been warming by less than 0.05 °C/year since 2000. Furthermore, precipitation had an insignificant decreasing trend for almost all ecoregions over the past two decades. The annual coherency between NDVI and LST was found much stronger than the annual coherency between NDVI and precipitation. The annual cycles of NDVI and LST were out-of-phase for the southern ecoregion while the annual cycle of precipitation led the one in NDVI by about one month for this ecoregion, the only ecoregion showing the highest Pearson correlation (53%) and annual coherency (39%) between NDVI and precipitation. For other ecoregions, the annual cycles of NDVI and LST were approximately in-phase, i.e., less than a month phase delay.
•Ecoregions of Italy have been slightly greening over the past two decades.•Italian ecoregions have been warming with various rates since 2000.•Significant annual coherency was observed between NDVI and LST.•NDVI and LST annual cycles were out-of-phase in the southern ecoregion.•NDVI and precipitation were significantly coherent in the southern ecoregion.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Remote sensing is undoubtedly one of the most practical approaches used in many fields such as structural health monitoring. The most notable deal of this method, however, is the data which are ...either missing or not given by satellites. In this study, an attempt has been made to propose machine learning (ML)-based models for reconstructing missing InSAR data (i.e., buildings’ displacement) to monitor their performance more properly. To this end, buildings located in the historical center of Rieti, Rome (Italy), are considered as case studies. Displacement of the points situated on different buildings’ roof, given by remote sensing, is utilized for training the relationship between inputs and outputs to the models. The input variables were points’ coordinates, height, and soil condition, while the cumulative displacement was the target output. Tree-based techniques namely decision tree, random forest and XGBoost were implemented for developing prediction models. The accuracy of the models was assessed through common performance metrics and Taylor diagram, and the most accurate model was introduced accordingly. The results demonstrated high capability of the tree-based methods for estimating the displacement of buildings. The proposed prediction models could be used for either predicting or reconstructing missing displacement of buildings at any specific point which ease structural performance monitoring remarkably.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Deep-seated gravitational slope deformations (DSGSDs) show a wide range of geomorphological characteristics and kinematic behaviours. In many cases, deforming rock masses move on a continuous surface ...or a thick basal shear zone (BSZ) overlying the stable bedrock. The nature of this boundary is a significant issue in scientific debates since examples of BSZs have been observed or inferred in some DSGSDs worldwide. In the central Apennines, although several cases of DSGSDs have been described in recent decades, no evidence of BSZs has been documented thus far.
This work presents the first case of a BSZ found in the region at the bottom of a large-scale gravitational deformation that affects the Mesozoic-Cenozoic carbonate ridge overhanging the Luco dei Marsi village (Abruzzi region). The BSZ consists of several metres-thick, cataclastic breccia developed within middle-Upper Cretaceous biodetritic limestone. The breccia level is exposed for approximately 200 m with a subhorizontal geometry and shows severe rock damage and weathering.
The DSGSD hosting the BSZ affects an NNW-SSE-oriented and wide Miocene anticline whose eastern limb is dismembered by Pliocene-Quaternary normal faults delimiting the edge of a large Quaternary intermontane basin (the Fucino Basin). Field survey, aerial photointerpretation, and remote sensing (DInSAR technique) analyses outline an active gravity-driven process. This is characterized by several kinds of geomorphological features, including downhill- and uphill-facing scarps, ridge-top depressions, gravitational grabens and trenches in the upper and middle parts of the ridge, and bulging at the toe of the slope. These features, which can be distinguished from tectonic elements due to their shape and extension, are an indication of a high degree of internal deformation and a compound sagging geometry for the Luco dei Marsi DSGSD.
The short-term activity of the process was revealed by DInSAR time series covering almost thirty years of satellite datasets, including ERS1/2, ENVISAT, COSMO-SkyMed, and SENTINEL 1 constellations. Strain rates on the order of a few mm/yr were inferred, with a marked difference between different sectors of the DSGSD area. The long-term (y > 102) lifespan of the DSGSD was framed into a multiple-step conceptual model summarizing the Early Pleistocene-Holocene geological evolution of the area. The model results outline the control exercised by extensional tectonics on DSGSD development, as progressive displacements along normal faults in the latest Pleistocene were the cause of lateral unconfinement at the toe of the slope.
This work further contributes to the increasing knowledge on DSGSDs in the central Apennines and the understanding of the relationship between deformation features induced by slope morphogenesis, such as the BSZ, and Quaternary tectonics within the mountain belt.
•An unknown case of DSGSD found in the central Apennines is presented.•For the first time a basal shear zone was observed in the mountain belt.•DInsar datasets elaboration proved the present state of activity of the DSGSD.•Slope deformation was originated by Quaternary normal faulting along the footslope.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The results of a study on gravitational induced lateral spreading phenomena are here reported. The lateral spreading processes are widely represented in the Italian Apennines due to the widespread ...overlapping of stiff rock masses on more ductile ones. The stress–strain evolution of these processes was investigated by combining an analogical and a numerical modelling approach. The analogue modelling reproduced the evolution of a carbonate ridge thrust over a clayey flysch with reference to the case-study of Mt. Roccatagliata–Mt. Sant'Angelo ridge. The rock mass juxtaposition was reproduced in a laboratory experiment by overlapping a brittle concrete on a viscous ductile material; these materials were selected with rheological properties, physically scaled with respect to the natural rock mass prototypes. The spreading phenomenon was modelled by opening horizontal panels in sequential stages and monitoring the resulting stresses within the ductile material during the experiment. A stress–strain modelling was also performed by an FDM numerical solution; this modelling replied the laboratory experiment by testing the use of different rheological constitutive laws. The resulting stresses and morphological evolutions are comparable with the analogical laboratory experiment only if a time-dependent rheological behaviour is assumed for the ductile material. The results show that lateral spreading processes can be properly investigated by combining analogue and numerical modelling techniques which take into account the viscous-plastic behaviour of the used materials.
•We reproduced the lateral spreading process by means of physical-analogue modelling.•Experimental results were validated via numerical modelling.•Both model are consistent with field evidences.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
This paper illustrates the potential of Sentinel-1 for landslide detection, mapping and characterization with the aim of updating inventory maps and monitoring landslide activity. The study area is ...located in Molise, one of the smallest regions of Italy, where landslide processes are frequent. The results achieved by integrating Differential Synthetic Aperture Radar Interferometry (DInSAR) deformation maps and time series, and Geographical Information System (GIS) multilayer analysis (optical, geological, geomorphological, etc.) are shown. The adopted methodology is described followed by an analysis of future perspectives. Sixty-two landslides have been detected, thus allowing the updating of pre-existing landslide inventory maps. The results of our ongoing research show that Sentinel-1 might represent a significant improvement in terms of exploitation of SAR data for landslide mapping and monitoring due to both the shorter revisit time (up to 6 days in the close future) and the wavelength used, which determine an higher coherence compared to other SAR sensors.
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