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The present study focused on novel rheometrical tool for the determination of the rheological behavior of large particle mixtures with particular interest in the application to granular materials involving in fast landslides as mud and debris flows. The main goal is the development of the Sphere Drag Rheometer (SDR), a home-made large-scale rheometer that allow to estimate the rheological properties of these mixtures considering particles up to 50 mm grain size. The SDR is composed of a sphere rigidly joined to a support that moves at constant velocity into the mixture. Compared to standard rheometer, the SDR uses much higher volume of mixtures of wider grain size distribution next to that in situ. Several pyroclastic soils collected from the source area of debris flows occurred in Campania region (Southern Italy) were analyzed. The paper reports the experimental results on fine particles mixtures, large particle mixtures, and their comparison. The experimental results on fine mixture are compared with those obtained by conventional rheometrical tools reported in previous papers. [ABSTRACT FROM AUTHOR]

Recent events, including the floods in central Europe in May 2021, have highlighted how climate change is giving rise to scenarios that were neither foreseen nor predictable. One problem this poses is the need to rethink the logic of various environmental constraints that are often based on return times of 20-50 years or 100-200. A single event does not change the statistical expectations for the recurrence of the event itself, but the recurrence of several extraordinary events in a few years is a clear indication of a changing trend. The prevention of the effects of such events is based on the definition of the areas at greater or lesser risk specifically based on the return times of the exceptional events, so it is foreseeable that a series of territorial plans, mostly carried out a few decades ago, will have to be updated or re-executed from scratch. These reworkings will be able to take advantage of the opensource software and open spatial data that have become available in the meantime, facilitating the entire process, and making it more open and shareable. In this paper we tested on a real case (the May 1999 pyroclastic flows in Campania, southern Italy) the actual possibility of implementing a model for forecasting such events using only open-source software and open data. It has been demonstrated that the entire process can be carried out using only open-source resources and it has been verified that the predictions of the hazard and risk model obtained with only input data prior to the event, give an output prediction that is significantly coincident with the events that actually occurred as documented by the authorities. [ABSTRACT FROM AUTHOR]

This paper intends to show basic strategies and technical solutions that may reduce the consequence of a volcanic eruption on buildings. One of the most dangerous eruptive phenomena is pyroclastic flow, a gas-solid mixture which can flow slope down up to reach considerable distances from the point of emission, with a speed that can easily exceed 100 km/h (~30 m/s). The damage caused by the impact on buildings depends on the combination of several factors: the duration of phenomenon, the temperature of flow and the pressure produced by the impact. The study tries to define a design-oriented approach of retrofitting and new construction with specific reference to the possible eruption of Vesuvio or Campi Flegrei in the Campania Region of Italy. For both red areas, which are directly affected by the flows, the Department of Civil Protection defined only one solution, that is the preventive evacuation. Whilst through the proposed mitigation strategy, the task is to establish a resilient sector within the red areas where buildings can withstand pressure and temperature in order to achieve both economic benefits and make reconstruction easier. [ABSTRACT FROM AUTHOR]

The assessment of the modulus of elasticity and compressive strength of masonry is a fundamental step in the seismic analysis of existing structures. In this paper, the representativeness of the values provided by flat-jack tests for tuff masonry is investigated through the analysis of a very large and homogeneous number of tests (635 double flat-jack tests). Data relate to existing buildings belonging to different historical and/or construction periods, located throughout the Campania region (Italy) in areas with different peculiarities. Results are compared with the values provided by Italian Building Code, containing ranges of the elastic modulus and compressive strength for different types of masonry. The values of flat-jack tests are then compared with laboratory tests available in the literature. Finally, comparisons with code equations are performed. It is shown that equations correlating the masonry compressive strength with the modulus of elasticity provide values larger than the mean of experimental data, whereas the equations correlating the masonry compressive strength with the strength of components provide lower values, if block and mortar strengths are varied within a probable and wide range. [ABSTRACT FROM AUTHOR]

• Italian cities are characterized by the presence of numerous masonry buildings of historical and architectural value. • Different masonry types are investigated, in order to define the mechanical behaviour. • The calibration of materials parameters for the modelling of typical tuff masonry systems spread in Campania area is given. • The results of the experimental tests carried out were compared with a FEM model exploiting CDP failure criterion. • A wall subjected to horizontal actions has been investigated with reference to solid and shell elements. The masonry buildings represent the largest portion of the Italian building heritage considering that about eighty percent of buildings is made of different kind of masonry. Italian cities are characterized by the presence of numerous masonry buildings of historical and architectural value. It is possible to find a large variety of building techniques and constructional material leading to different masonry structures that need to be precisely characterized as regards the mechanical behaviour. In this paper, the calibration of the materials parameter for an adequate modelling of typical tuff masonry constructive systems spread in Campania region is given. The calibration has been developed reproducing, by FEM analysis, real compression tests performed in displacement control available in literature. In particular, reference is made to masonry with regular ashlars, listed tuff masonry and chaotic tuff masonry. The FEM analyses have been carried out considering the "Concrete Damaged Plasticity" failure criteria. Moreover, the modelling of a wall subjected to horizontal actions has been investigated with reference to solid brick elements and shell to analyse if there is any shape factor affecting the different response. It can be pointed out that the analytical model used for the calibration of uniaxial tension and compression curves shows great adaptability and versatility for each type of masonry. [ABSTRACT FROM AUTHOR]

The analysis of geological processes threatening people and properties in a populated region should be based on a comprehensive knowledge of historical events and related characteristics. This type of information is essential for predisposing event scenarios, validating prediction models, and planning risk mitigation measures. Such activities may be more complex in some geological settings, where urban settlements are exposed to multi-hazard conditions. This is the case of the densely populated Campi Flegrei volcanic area located in the Campania region, southern Italy. Here, volcanic and seismic hazards are associated with landslides, floods, and coastal erosion, which are playing a relevant role in the landscape modification. The CAmpi Flegrei LAndslide Geodatabase (CAFLAG), here presented, provides information related to 2302 landslides that occurred in the continental, coastal, and insular sectors of the study area during the 1828–2017 time interval. Data associated with the collected landslide events highlight the characteristics of both landslides and of the affected sites. Most of the cataloged mass movements consist of rock falls affecting rocky slopes formed by lithified volcanic rocks, such as tuff or ignimbrite. In addition, rainfall-induced earth and debris slides translating into debris avalanches or rapid flows are widespread along steep slopes mantled by weakly welded pyroclastic airfall deposits, similarly to other areas of the region. The highest density of landslides is concentrated along the coastline, where mass movements are contributing to the retreat of coastal cliffs, and along inland slopes exposed towards the western directions, where most of the storm systems come from. Temporal information shows peaks of landslides in the years 1986, 1997, and 2005. A total of 127 people lost their lives as a consequence of 53 cataloged landslides, with a frequency of deadly events observed however to have decreased since the early 1980s. This information will be useful to analyze mortality and risk conditions still affecting the population of the Campi Flegrei caldera, which should be fully addressed with advanced knowledge and accurate scenarios. The full database is freely available online at 10.4121/14440757.v2 (Esposito and Matano, 2021). [ABSTRACT FROM AUTHOR]

Pyroclastic soils are widespread in the world. In particular, they cover a great part of Campania, a densely populated country of Southern Italy, where some distinct volcanic centers are present. In these soils, precipitations can trigger fast flow-like landslides causing destruction and loss of human lives. The movement style, the high velocity and the long run-out of these landslides are an indication of the occurrence, in the saturated soil mass, of mechanisms of undrained instability due to the inability of soil to sustain the deviator stress related to the slope condition. This paper reports the results of a wide experimental laboratory program carried out on a volcanic ash, which recently has been the seat of a killer landslide, stressing the factors that govern the undrained response of these materials. [ABSTRACT FROM AUTHOR]

Abstract: Campania Region (Italy), one of the most densely populated areas in Europe, is probably the one with the highest risk of landslide. A large part of the region is covered by unsaturated cohesionless pyroclastic deposits subjected to rainfall-induced landslides. According to experience, these can display different features and magnitude. The most catastrophic landslides are liquefied debris flows which periodically occur on steep slopes, causing death and destruction in areas located downslope. Therefore, zoning of those areas which can be the source of liquefied debris flow is necessary. The paper reports some useful elements for zoning based on infinite slope analysis, accounting for the results of recent research on the mechanics of rainfall-induced landslides in pyroclastic soils. [Copyright &y& Elsevier]

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Debris flows that have occurred in the area of San Martino Valle Caudina (Campania, Southern Italy) are described by geomorphological and hydrological analyses, focusing on the recent event of December 2019. This area can be considered a key example for studying debris-flow phenomena involving the pyroclastic mantle that covers the karstified bedrock along steep slopes. A hydrological analysis of the time series of the maximum annual rainfall, of durations of 1, 3, 6, 12 and 24 h, was carried out based on a new approach to assess rainstorm magnitude. It was quantified by measuring the deviation of the rainfall intensity from the normal conditions, within a specified time period. As the time series of annual maxima are typically skewed, a preliminary transformation is needed to normalize the distribution; to obtain the Z-value of the standard normal distribution, with mean µ = 0 and standard deviation σ = 1, different probability distribution functions were fitted to the actual data. A specific boxplot was used, with box width Z = ±1 and whiskers length Z = ±2. The deviations from these values provide the performance of the distribution fits. For the normalized time series, the rates shown by the trends and relative significance were investigated for the available time series of 11 rain gauges covering the Western–Central Campania region. The most critical condition for the debris-flow initiation appears to occur when a severe or extreme rainfall has a duration ≥ 12 h. The trend analysis did not detect statistically significant increases in the intensity of the rainfall of duration ≥ 6 h. [ABSTRACT FROM AUTHOR]