Martelli L.,Servizio Geologico |
Santulin M.,Italian National Institute of Geophysics and Volcanology |
Sani F.,University of Florence |
Tamaro A.,National Institute of Oceanography and Applied Geophysics - OGS |
And 4 more authors.
Journal of Seismology | Year: 2017
Seismic hazard has been computed for the Northern Apennines in northern Italy based on a new seismogenic zonation. This zonation considers inclined (dipping) planes as seismogenic sources, defined on the basis of all the seismotectonic information available so far. Although these geometries are extremely rough because they simplify with a few inclined elements the totality of faults constituting a source, this model mimics the tectonic style better than that based on horizontal planes. Nevertheless, for a comparison between the new ground motions obtained and those available in the literature, the plane version of the zonation has been developed, where horizontal areas (the standard seismogenic zones), representing the surficial projection of the inclined planes, are used as seismogenic sources. © 2017 Springer Science+Business Media Dordrecht
Lanzo G.,University of Rome La Sapienza |
Silvestri F.,University of Naples Federico II |
Costanzo A.,University of Calabria |
d'Onofrio A.,University of Naples Federico II |
And 4 more authors.
Bulletin of Earthquake Engineering | Year: 2011
Following the April 6th, 2009 Abruzzo mainshock, the Italian Civil Protection Department promoted a multidisciplinary study aimed at developing seismic microzonation maps for post-earthquake reconstruction planning. In the framework of this project, a Working Group, including the authors, was assembled to carry out a microzonation study on six villages located in the Middle Aterno valley. This paper focuses on the villages of Castelnuovo and Poggio Picenze, which experienced MCS intensity values of IX-X and VIII-IX, respectively. 1D and 2D linear equivalent site response analyses were carried out on representative geological cross-sections through the damaged centres and the expansion zones. The subsoil models resulting from geological, geotechnical and geophysical investigations were calibrated by comparing numerical amplification functions, in the linear range, with horizontal-to-vertical spectral ratio derived from both aftershocks and noise recordings. The input motions adopted for the analyses were five artificial accelerograms compatible with three response spectra obtained from the Italian seismic code, as well as from ad hoc probabilistic and deterministic studies. The results were expressed in the form of horizontal profiles of amplification factors in terms of peak ground acceleration, FPGA, as well as of the Housner intensity, FH, in two different range of periods; this latter parameter was shown to be almost independent of the input motion and allowed to express the dependency of site amplification on the frequency range. The amplification factors computed along the representative geological sections were finally extended with a rational procedure to the surrounding areas to draw Grade-3 microzonation maps. © 2011 Springer Science+Business Media B.V.
Paolucci E.,University of Siena |
Albarello D.,University of Siena |
D'Amico S.,University of Malta |
Lunedei E.,University of Siena |
And 3 more authors.
Bulletin of Earthquake Engineering | Year: 2015
Results of an extensive ambient vibration surveys carried out by different research teams in the area damaged by May–June 2012 seismic sequence in Emilia Romagna (Northern Italy) are summarized and analysed. In particular, ambient vibrations were acquired by both single station and seismic array configurations. Average horizontal to vertical spectral ratios (HVSR) at single station measurements were considered to evaluate local resonance phenomena. Despite the fact that general trends that can be detected are the effect of the subsoil configuration, H/V spectral ratios show a significant dependence on meteo-climatic conditions: in particular, HVSR amplitudes in the low frequency range (<0.5 Hz) correlate significantly with the sea wave activity in the Central Mediterranean. Anyway, resonance frequencies estimated from HVSR peaks appear persistent and have been used to estimate the local depth of impedance contrasts responsible for seismic resonance phenomena. To this purpose, average VS values up to any depth (Formula presented.) were assessed in the form of a standard power law constrained by Rayleigh dispersion curves deduced from the seismic arrays, and borehole data. In the whole area (except in the Mirandola area) two significant interfaces have been identified corresponding to two main resonance frequencies around 0.8–0.9 and 0.25–0.3 Hz respectively. The first one is attributed to a seismic impedance contrast located in the depth range 60–110 m. The second one corresponds to a deeper interface, possibly located at several hundreds of meters of depth. As concerns the Mirandola area, a single interface has been identified with depths varying in the range 50–115 m corresponding to resonant frequencies in the range 0.8–1.4 Hz. Finally a tentative geological interpretation of the above resonant interfaces is presented. © 2015 Springer Science+Business Media Dordrecht
Milani G.,Polytechnic of Milan |
Bucchi A.,Servizio Geologico
Composite Structures | Year: 2010
Masonry curved structures, as for instance arches, domes and vaults, are very diffused in historical and existing structures and usually require seismic upgrading and/or rehabilitation. Where FRP external strips cannot be applied for some reasons, the utilization of FRP bars embedded near the external surface becomes a very interesting and effective alternative. In this paper, a kinematic Finite Element limit analysis model to predict collapse loads and failure mechanisms of masonry curved structures reinforced with near surface mounted FRP bars regularly distributed is presented. Reinforced masonry homogenized failure surfaces are obtained by means of a compatible identification procedure, where a central brick is supposed interacting with its neighbors by means of finite thickness mortar joints, filler epoxy resin and FRP rods. In the model, it is required only that the curved structure results from a periodic disposition of bricks, mortar and FRP bars. Therefore, any pattern (multi-leaf, multi-head and single leaf) may be potentially investigated with the procedure proposed. In the framework of the kinematic theorem of limit analysis, a simple constrained minimization problem is obtained on the unit cell, suitable to estimate - with a very limited computational effort - reinforced masonry homogenized failure surfaces. A FE strategy is adopted to solve the homogenization problem at a cell level, modeling joints, bricks, filler and FRP rods by means of 8-noded infinitely resistant parallelepiped elements. A possible jump of velocities is assumed at the interfaces between contiguous elements, where plastic dissipation occurs. For mortar and bricks interfaces, a frictional behavior with possible limited tensile and compressive strength is assumed, whereas for epoxy resin and FRP bars some formulas available in the literature are adopted in order to take into account in an approximate but effective way, the delamination of the bar from the epoxy and the failure of the filler at the interface with the joint. In order to validate the model proposed, two numerical examples are analyzed, consisting of a circular masonry arch and a hemispherical dome. For both the examples presented, comparisons with experimental evidences, where available, and alternative non-linear FE procedures are reported. Reliable predictions of collapse loads and failure mechanisms are obtained with the model proposed for all the cases analyzed, meaning that the approach may be used by practitioners for a fast and reliable evaluation of the effectiveness of a strengthening intervention. © 2010 Elsevier Ltd.
Tonni L.,University of Bologna |
Gottardi G.,University of Bologna |
Amoroso S.,INGV |
Bardotti R.,University of Florence |
And 19 more authors.
Rivista Italiana di Geotecnica | Year: 2015
The seismic sequence that in May 2012 struck a large area of the river Po Valley (Emilia-Romagna region, Northern Italy) triggered significant fractures and deformations in a number of riverbanks located close to the earthquake epicenter. Among them, one of the most severely damaged structures turned out to be the banks of an irrigation canal known as Canale Diversivo di Burana, flowing through the small village of Scortichino (Municipality of Bondeno), near the historic town of Ferrara. Large, longitudinally-oriented ground cracks were observed along a 3 km bank stretch, causing in turn severe structural damages to a large part of the approximately one hundred houses and productive activities built on the bank crown. In order to interpret the response of such soil structure during the 2012 earthquake by identifying possible damage causes as well as to suggest relevant remedial measures and seismic risk mitigation actions towards possible future earthquakes, the Emilia-Romagna regional authority launched an in-depth study carried out by a number of research groups from various Italian universities in cooperation with technical experts of the Geological, Seismic and Soil Survey Regional Department. To this purpose, a number of geotechnical investigations were performed (in situ and laboratory tests) and an accurate geotechnical model for the seismic stability analyses was thus defined. Potential liquefaction phenomena of the shallow sandy soils, in the foundation subsoil, were taken into account in the analyses. The paper describes the main features of the extensive study carried out by the working group and summarizes the most significant achievements of the analyses. © 2015, Patron Editore S.r.l. All rights reserved.
Piccinini L.,University of Padua |
De Nardo M.T.,Servizio Geologico |
Filippini M.,University of Bologna |
Segadelli S.,Servizio Geologico |
And 2 more authors.
Geoingegneria Ambientale e Mineraria | Year: 2014
The paper deals about the mapping of contribution and well-head protection areas for springs discharging out from non karstic fractured aquifers. In the specific case we refer to mainly sedimentary hard rock aquifers occurring in Northern Apennines (Italy): They are represented by turbidites and arenites, and by ophiolites at a lower extent, characterized by high heterogeneity and anisotropy in the hydraulic conductivity distribution. Groundwater flow numerical modeling, by the adoption of Equivalent Porous Medium (EPM) approach, is presented as the most suited and robust tool in order to locate, according to a physically based approach, contribution and protection areas of springs; the main mandatory prerequisites are the availability of a reliable geological model derived from a detailed geological survey of the area and the occurrence of multi-year time series of continuous monitoring of spring discharge. The presented case study is about a main public water supply spring and, at the same time, a Groundwater Dependent Ecosystems (GDE) of paramount importance in the area. The application is preceded by a review of different methodologies employed to map non karstic spring contribution and protection areas, updated with recent references. The recharge area derived by numerical modeling has an extension of about 2.40 km2, this area produces an average spring flow rate of 12.43 l/s. Spring protection areas were defined by the envelop of the 60 days and 365 days travel times. Their extensions are, respectively, 1.6% and 11.4% of the recharge area. Finally, the infiltration coefficient, above the contribution area, resulted equal to 17%. At the end of the article a hybrid methodology to map contribution and protection areas of springs in a mountainous non karstic setting is proposed.
Villa P.,CNR Institute for Electromagnetic Sensing of the Environment |
Malucelli F.,Servizio Geologico |
Scalenghe R.,University of Palermo
IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing | Year: 2014
Peri-urban areas are the extension of cities into contiguous areas, where households and farms coexist. Carbon stocks (CSs) assessment, a concept here extended to urban features, has not yet been studied in depth over peri-urban areas due to uncertainties in such CSs quantification, level of detail required about construction materials, and the high spatial variability of those stocks. Remote sensing (RS)-based techniques have been successfully utilized in urban areas for assessing phenomena such as soil sealing, sprawl patterns, and dynamics of surface imperviousness, especially focusing on land cover classification at high to medium spatial scales. Over the floodplain study area of Emilia-Romagna region (Italy), we compared mapping products derived from Landsat multiseasonal data with different CSs, in soils and impervious surfaces, such as buildings and roads. A multiscale correlation analysis and regression assessment between CSs layers and satellite products were run at different grid cell sizes (100, 250, 500, and 1000 m). Results show that RS products from processing of mid-resolution satellite data can effectively perform well enough to estimate CSs in peri-urban areas, especially at 500-1000 m scale. Urban Fraction Cover method, derived through weighting urban land cover classes (including dense, sparse, and industrial urban features) can represent a good proxy of the ratio of anthropogenic over natural CSs (R2 up to 0.75). Imperviousness Index (II) product scored high positive correlation with CSs over built-up areas (R2 up to 0.77), and strong negative correlation with organic carbon density in soil (R2 up to 0.73). © 2014 IEEE.
Harley M.,University of Ferrara |
Valentini A.,ARPA SIMC HydroMeteoClimate Service of Emilia Romagna |
Armaroli C.,University of Ferrara |
Ciavola P.,University of Ferrara |
And 3 more authors.
Proceedings of the Coastal Engineering Conference | Year: 2012
The ability to predict the imminent arrival of coastal storm risks is a valuable tool for civil protection agencies in order to prepare themselves and, if needs be, execute the appropriate hazard-reduction measures. In this study we present a prototype Early Warning System (EWS) for coastal storm risk on the Emilia-Romagna coastline in Northern Italy. This EWS is run by executing a chain of numerical models (SWAN, ROMS and XBeach) daily, with the final output transformed into a format suitable for decision making by end-users. The storm impact indicator selected for this site is the Safe Corridor Width (SCW), which is a measure of how much dry beach width is available for safe passage by beach users. A three-day time-series of the predicted SCW is generated daily by the prototype EWS. If the minimum SCW exceeds a certain threshold, a warning is issued to end-users via an automated email service. All available prediction information is also updated daily on-line. Over the one year that the EWS has been operating (June 2011 until June 2012), 13 "code red" and 16 "code orange" warnings have been issued, with the remaining 305 predictions indicating low hazard in terms of the SCW. The reliability of the predictions from the perspective of the end-user has meant that the EWS is currently being expanded to include the entire Emilia-Romagna coastline.
Armaroli C.,University of Ferrara |
Ciavola P.,University of Ferrara |
Perini L.,Servizio Geologico |
Calabrese L.,Servizio Geologico |
And 3 more authors.
Geomorphology | Year: 2012
The definition of storm morphological thresholds along the coast of the Emilia-Romagna Region strictly depends on its configuration and variability. The region is located in northern Italy, facing the Adriatic Sea. The coastline is characterised by very different levels of economic development, ranging from natural zones with dunes to highly developed stretches protected by breakwaters and groynes. The Integrated Coastal Zone Management effort is mainly concentrated on preserving urban areas that generate significant income for the regional economy. Natural areas, while small in comparison to the urbanised zone, are important for environment preservation. Because of such a multiplicity of issues at stake, it was decided to produce two different thresholds: one for the morphological impact on natural sectors and another for inundation and damage to structures along urbanised zones. The "forcing" component of the threshold definition for natural areas was calculated by summing the effects of surge + tide + waves (run-up elevation) to find the Maximum Water Level (MWL) reached by the sea during one, ten and one-hundred year storm return periods. For urbanised zones, historical storm information was collected starting from the 1960s in order to identify the forcing conditions causing real damages. Each storm was classified in terms of wave height, period, direction and surge level. Morphological information were obtained from Lidar flights performed in 2003 and 2004 and from direct surveys undertaken in September 2008 and February 2009 as part of the monitoring programme for the MICORE Project. The computed MWL for each return period was then compared to beach elevations along natural areas in order to calculate the Dune Stability Factor (DSF), an index that accounts for the eroded sediment volume above the MWL during a storm. Based on analysis along 41 profile lines at a 500. m spacing, it was found that the 1-in-1. year return period wave height + 1-in-1. year return period surge are able to erode and/or overwash 2/3 of the dunes. The historical storm hydrodynamic information was used to estimate which wave and surge conditions are able to inundate at least 2/3 of the beach profiles. The MWL was again compared to beach elevations, this time along 63 anthropogenic profiles spaced 500. m apart (or 1/3 of the urbanised coastline). It was found that a wave heights >= 2. m and surge + tide levels >= 0.7. m are able to flood between 18% and 36% of the built-up coast. The defined thresholds are related to the present coastal characteristics and are not "static", meaning that they are likely to change according to future evolution of the coastline. They are very important because they can be used as thresholds to issue warnings and alert the Civil Protection. Moreover they are the first thresholds defined for the Emilia-Romagna coastline and will be used as starting values to generate "dynamic" thresholds based on numerical model predictions of morphological change for a given wave and surge level. © 2011 Elsevier B.V.
Bruno L.,University of Bologna |
Amorosi A.,University of Bologna |
Severi P.,Servizio Geologico |
Italian Journal of Geosciences | Year: 2015
Palaeosol-based correlations within the Late Pleistocene- Holocene alluvial succession along the Reno River, in the southern Po Plain, enabled the identification of depositional cycles falling in the sub-Milankovitch band. Each cycle, composed of overbank and fluvial facies capped by poorly to weakly developed palaeosols, is correlatable upstream to a single fluvial terrace in the Reno River valley and to an individual channel belt close to the valley outlet. Four cycles, dated to about 15-10 (c1), 10-5.5 (c2), 5.5-1.5 (c3) and <1.5 (c4) cal ky BP, respectively, were identified within the Ravenna subsynthem (AES8), an unconformity-bounded unit of the Geological Map of Italy to scale 1:50,000, corresponding to the post-Last Glacial Maximum deposits. This unit, typically wedge-shaped in coastal areas, where it consists of retrogradational (coastal plain and estuarine) deposits overlain by progradational (deltaic) facies, at the basin margin is a mud-dominated alluvial succession deposited atop laterally extensive fluvial-channel complexes. The base of AES8, correlatable to the transgressive surface identified in the coastal area, is a palaeosol dated to about 18-15 ky BP. The bounding surfaces of the high-frequency cycles are diachronous along the Reno longitudinal profile, and not necessary associated to remarkable lithological contrasts, but can be detected even in mud-dominated successions. Climate change likely exerted a major control in triggering alternating phases of river aggradation and degradation, with an increasing contribution of anthropogenic factors since the middle-late Holocene. Based on the correlation of 34 core logs and 33 well descriptions, with the aid of 71 radiocarbon dates, this study highlights to what extent palaeosols can represent powerful stratigraphic tools to identify cyclic patterns in alluvial successions, even at the millennial time scale. © Società Geologica Italiana, Roma 2015.