HIRESSS: a physically based slope stability simulator for HPC applications

HIRESSS (<b>HI</b>gh <b>RE</b>solution <b>S</b>lope <b>S</b>tability <b>S</b>imulator) is a physically based distributed slope stability simulator for analyzing shallow landslide triggering conditions in real time and on large areas using parallel computational techniques. The physical model proposed is composed of two parts: hydrological and geotechnical. The hydrological model receives the rainfall data as dynamical input and provides the pressure head as perturbation to the geotechnical stability model that computes the factor of safety (FS) in probabilistic terms. The hydrological model is based on an analytical solution of an approximated form of the Richards equation under the wet condition hypothesis and it is introduced as a modeled form of hydraulic diffusivity to improve the hydrological response. The geotechnical stability model is based on an infinite slope model that takes into account the unsaturated soil condition. During the slope stability analysis the proposed model takes into account the increase in strength and cohesion due to matric suction in unsaturated soil, where the pressure head is negative. Moreover, the soil mass variation on partially saturated soil caused by water infiltration is modeled. <br><br> The model is then inserted into a Monte Carlo simulation, to manage the typical uncertainty in the values of the input geotechnical and hydrological parameters, which is a common weak point of deterministic models. The Monte Carlo simulation manages a probability distribution of input parameters providing results in terms of slope failure probability. The developed software uses the computational power offered by multicore and multiprocessor hardware, from modern workstations to supercomputing facilities (HPC), to achieve the simulation in reasonable runtimes, compatible with civil protection real time monitoring. <br><br> A first test of HIRESSS in three different areas is presented to evaluate the reliability of the results and the runtime performance on large areas

Combination of rainfall thresholds and susceptibility maps for dynamic landslide hazard assessment at regional scale

We propose a methodology to couple rainfall thresholds and susceptibility maps for dynamic landslide hazard assessment at regional scale. Both inputs are combined in a purposely-built hazard matrix to get a spatially and temporally variable definition of landslide hazard: while statistical rainfall thresholds are used to accomplish a temporal forecasting with very coarse spatial resolution, landslide susceptibility maps provide static spatial information about the probability of landslide occurrence at fine spatial resolution. The test site is the Northern part of Tuscany (Italy), where a recent landslide susceptibility map and a set of recently updated rainfall thresholds are available. These products were modified and updated to meet the requirements of the proposed procedure: the susceptibility map was reclassified and the threshold set was expanded defining additional thresholds. The hazard matrix combines three susceptibility classes (S1, low susceptibility; S2 medium susceptibility; S3 high susceptibility) and three rainfall rate classes (R1, R2, R3), defining five hazard classes, from H0 (null hazard) to H4 (high hazard). A key passage of the procedure is the appropriate calibration and validation of the matrix, letting the hazard classes have a precise meaning in terms of expected consequences and hazard management. The employ of the proposed procedure in a regional warning system brings two main advantages: (i) it is possible to better hypothesize when and where landslide are expected and with which hazard degree, thus fostering a more effective hazard and risk management (e.g., setting priorities of intervention); (ii) the spatial resolution of the regional scale warning system is markedly refined because from time to time the areas where landslides are expected represent only a fraction of the alert zone

Large-scale risk analysis in the Arno river basin (Italy)

We present the methodologies adopted and the outcomes obtained in the analysis of landslide risk in the basin of the Arno River (Central Italy) in the framework of a project sponsored by the Basin Authority of the Arno River, started in the year 2002 and completed at the beginning of 2005. A new landslide inventory of the whole area was realized, using conventional (aerialphoto interpretation and field surveys) and non-conventional methods (e.g. remote sensing techniques such as DInSAR and PS-InSAR). The great majority of the mapped mass movements are rotational slides (75%), solifluctions and other shallow slow movements (17%) and flows (5%), while soil slips, and other rapid landslides, seem less frequent everywhere within the basin. The assessment of landslide hazard in terms of probability of occurrence in a given time, based for mapped landslides on direct and indirect observations of the state of activity and recurrence time, has been extended to landslide-free areas through the application of statistical methods implemented in an artificial neural network (ANN). Unique conditions units (UCU) were defined by the map overlay of landslide preparatory factors (lithology, land cover, slope gradient, slope curvature and upslope contributing area) and afterwards used to construct a series of model vectors for the training and test of the ANN. Model validation confirms that prediction results are very good, with an average percentage of correctly recognized mass movements of about 85%. The analysis also revealed the existence of a large number of unmapped mass movements, thus contributing to the completeness of the final inventory. Temporal hazard was estimated via the translation of state of activity in recurrence time and hence probability of occurrence. The definition of position, typology and characteristics of the elements at risk has been carried out with two different methodologies, partially derived from the “Plans d’Exposition au Risque” proposed in France: i) buildings and infrastructures were directly extracted from digital terrain cartography at the 1:10,000 scale, whilst ii) nonurban land use was identified and mapped based on an updated and improved CORINE land cover map at the 1:50,000 scale. The definition of the exposure of the elements at risk relies upon contingent valuation methods and form-based interviews. Landslide intensity, usually defined as proportional to kinetic energy, was obtained considering landslide typology as a proxy for expected velocity. In the case of the Arno River Basin the definition of intensity is influenced by the fact that the large majority of mass movements are deep-seated reactivated slides evolving into flows. Two main cases were so considered: deep-seated rotational slides and shallow flows or planar slides with virtually constant depth. In the latter case, intensity as a function of volume was set proportional to the area of the mapped phenomenon. In the former case, a simple geometric model was used to compute the volume. Intersection of hazard values with vulnerability and exposure figures, obtained by reclassification of digital vector mapping at 1:10,000 scale, lead to the definition of risk values for each terrain unit for different periods of time into the future. Numerical results indicate that in absence of mitigation measures, large economic losses must be expected due to landslide activity in the few next years. The final results of the research are now undergoing a process of integration and implementation within land planning and risk prevention policies and practices at local and national level

A methodological approach of QRA for slow-moving landslides at a regional scale

Landslides represent a serious worldwide hazard, especially in Italy, where exposure to hydrogeological risk is very high; for this reason, a landslide quantitative risk assessment (QRA) is crucial for risk management and for planning mitigation measures. In this study, we present and describe a novel methodological approach of QRA for slow-moving landslides, aiming at national replicability. This procedure has been applied at the basin scale in the Arno River basin (9100 km(2), Central Italy), where most landslides are slow-moving. QRA is based on the application of the equation risk = hazard (H) × vulnerability (V) × exposure (E) and on the use of open data with uniform characteristics at the national scale. The study area was divided into a grid with a 1 km(2) cell size, and for each cell, the parameters necessary for the risk assessment were calculated. The obtained results show that the total risk of the study area amounts to approximately 7 billion €. The proposed methodology presents several novelties in the risk assessment for the regional/national scale of the analysis, mainly concerning the identification of the datasets and the development of new methodologies that could be applicable over such large areas. The present work demonstrates the feasibility of the methodology and discusses the obtained results

Comparison of three treatment protocols with intra-articular low or intermediate molecular weight hyaluronic acid in early symptomatic knee osteoarthritis

Introduction: Viscosupplementation with hyaluronic acid (HA) is indicated for non-responders to non-pharmacological therapy, to analgesics or when non-steroidal anti-inflammatory drugs (NSAIDs) are contraindicated. The aim of this study is to compare the efficacy, safety and costs of three different HA treatments (Sinovial® Forte, sinovial one and hyalgan). Patients and methods: Ninety patients with grade I/II Kellgren–Lawrence knee osteoarthritis were included in three groups, the first was treated with hyalgan (weekly for 5 weeks), the second with Sinovial® Forte (weekly for 3 weeks) and the third group with a single injection of sinovial one. Results: All three treatments were effective, with an average reduction in the Western Ontario and McMaster Universities osteoarthritis index (WOMAC) score of 18.9 points for hyalgan, 18.04 points for Sinovial® Forte and 17.92 points for sinovial one. The comparison of the three groups did not show any statistical difference in terms of efficacy. National health system (NHS) and social costs are, respectively, €419.12 and €853.43 for hyalgan, €338.64 and €599.22 for Sinovial® Forte, €221.56 and €308.42 for sinovial one. Conclusion: All three treatments were equally effective with no statistically significant differences; thus, the treatment with sinovial one may be considered as clinically effective as the other two regimens, but with a very efficient cost profile in early symptomatic knee osteoarthritis

Crosscultural Validation of the Community Integration Questionnaire-Revised in an Italian Population

Objective. The aims of this study are the translation, cultural adaptation, and validation of the Community Integration Questionnaire-Revised (CIQ-R) in Italian in a group of individuals with no clinical evidence of disability. Methods. The test's internal consistency and validity were assessed by following international guidelines. The test's internal consistency was examined using Cronbach's alpha (α) coefficient. Pearson's correlation coefficient was calculated to assess the test's concurrent validity compared with the Short Form-12 (SF-12) health survey. Results. The CIQ-R was administrated to 400 people with no clinical evidence of disease, impairment, or disability, aged between 18 and 64. Cronbach's α reported a value of 0.82 in the home integration subscale. The test also showed a good test-retest reliability, with an Intraclass Correlation Coefficient of 0.78, and a significant correlation between the total score of the CIQ-R and the Physical Component Summary (PCS) of the SF-12 (r=0.118), between the "social integration"subscale's score and PCS12 (r=0.121) and between the "Electronic Social Networking integration"subscale's score and PCS12 (r=0.184), with p<0.05. Conclusion. This is the first study to report the results of the translation and validation of the CIQ-R in Italian. The CIQ-R is an important tool for Italian professionals and can be useful in both clinical practice and research for measuring the level of community integration among the healthy population