1,721,011 research outputs found
Incorporating results from seismic microzonation into probabilistic seismic hazard analysis: an example in western Liguria (Italy)
No full textThis study presents a first attempt to couple two of the most important components of seismic risk mitigation strategies: probabilistic seismic hazard analysis (PSHA) and seismic microzonation. We show an application in the westernmost sector of the Liguria region in northwestern Italy, an area where strong earthquakes (up to about magnitude 6.5) occurred in the past producing hundreds of casualties. The final goal is to produce probabilistic seismic hazard maps for peak ground acceleration and spectral acceleration that incorporate site amplification (by amending existing ground motion attenuation models for rock conditions with an additional amplification term provided by microzonation studies) on a municipal scale. To this end, a partially non-ergodic approach is applied according to modern practice. Compared to conventional, ergodic hazard assessments for rock conditions and flat topography, such maps provide at a glance a finer picture of the actual hazard of the area under study, highlighting those sites where the ground motion hazard is dominated by local amplification effects. At these sites, the expected ground motions are up to twice the values resulting from the traditional, ergodic PSHA on rock. Besides hazard maps, results are also presented in terms of uniform hazard spectra for a number of target sites. Comparison with the isoseismal maps of past earthquakes have revealed a good agreement between the spatial distribution of the assessed hazard and that of felt intensities, with greater damage observed in areas presenting significant amplification effects and, consequently, a higher seismic hazard
UPDATE OF THE LIQUEFACTION TRIGGERING MAP OF ITALY
No full textWe present an update of the map of liquefaction triggering potential of Italy (Barani et al., 2023), MILQ (Mappa del potenziale d’Innesco della LiQuefazione), along with the related web service (www.distav.unige.it/rsni/milq.php). The map, which classifies sites in terms of liquefaction triggering potential, relies on two main source data: the seismic hazard map of Italy (MPS Working Group, 2004; Stucchi et al., 2011) and the related hazard disaggregation (Barani et al., 2009). Such input data allow us to verify whether the triggering condition proposed by the Italian Guidelines for Seismic Microzonation (SM Working Group, 2008 and 2015) is met; namely, liquefaction is expected to be triggered at a site if the expected seismic events are characterized by magnitude values Mw ≥ 5 and produce a surface peak ground acceleration amax ≥ 0.1 g. If the condition above is not verified, at least in principle, we can assume that the area under study is not susceptible to liquefaction. In this study, we incorporate the results of seismic hazard disaggregation for a response period T = 0.5 s, previously unreleased. In our original work, the disaggregation of the spectral acceleration hazard for T = 1.0 s was considered indiscriminately to define the reference magnitude for all ground types that, according to the Italian building code (Ministero delle Infrastrutture e dei Trasporti, 2018), identify sites characterized by deposits of loose-to-medium cohesionless soil (i.e., ground types C, D, and E). However, while sites classified as ground type C and D should present soil deposits with thickness greater than 30 m, type E sites should be characterized by thinner soils, resulting in a decrease in the values of the resonance period. Thus, the additional information about the magnitudes that contribute most to the spectral acceleration hazard for T = 0.5 s, while representing a refinement of the original map and a simple improvement to our web service, is a valuable information for the end user who needs to decide whether liquefaction in a given area is a hazard that may (or may not) deserve further investigation. In addition to the update of the original map of liquefaction triggering potential, which refers to a return period of 475 years, maps for return periods of 975 and 2475 years are presented
Perspectives of agrivoltaic systems in the Italian context
No full textThe current energy transition increasingly requires the installation of renewable generators, which, because of their extent, may be opposed by local communities. Therefore, their acceptability must necessarily come through careful integration into the landscape in which the generators will fit. One of the promising solutions being studied around the world is the integration of PV generators and agricultural production, trying to capture as much as possible the synergies between the two systems. The purpose of this article is to analyze the perspectives and guidelines to be followed for the implementation of agrivoltaic systems with a particular focus on the Italian reality and similar environments
Incorporation of long-term Persistence in the seismic process into probabilistic seismic hazard analysis
No full textNew insights into long-period (>1 s) seismic amplification effects in deep sedimentary basins: A case of the po plain basin of Northern Italy
No full textThis study investigates and quantifies the influence of the shallower deposits (down to few hundreds of meters) of the Po Plain sedimentary basin (northern Italy) on the long-period component (i.e., 1 s < T < 3 s) of seismic groundmotion, inwhich amplification effects due to the soft sediments above seismic bedrock were observed.A new seismostratigraphic model of the shallow deposits of the entire basin is provided with an unprecedented detail by taking advantage of recently acquired geophysical data. The seismostratigraphic model is used to simulate the groundmotion amplification in the Po Plain bymeans of extensive 1D ground response analysis. Results are compared with seismic observations available at a number of sites equipped with borehole seismic stations, where earthquakes have been recorded both at the surface and at the seismic bedrock depth. Despite the general agreement with observations concerning the seismic resonance frequencies, our model may fail in capturing the amplitude of the actual seismic amplification of the basin in the long-period range. We observe that 3D basin effects related to surface waves generated at the edge of the basin may play a significant role in those zones where seismic hazard is controlled by distant sources. In these cases, 1Dmodeling leads to average underestimations of 30%, up to a maximum of 60%. The amplification functions need to be corrected for a basin-effects correction term, which in this case is provided by the ground-motion prediction equation of the study area. The corrected amplification functions agree with the empirical observations, overcoming the uneven distribution of the recording stations in strong-motion datasets. These results should be taken into account in future seismic microzonation studies in the Po Plain area, where the 1D approach is commonly adopted in ground response analyses, and in site-specific seismic hazard assessments aimed at the design of structures that are sensitive to the long-period component of seismic groundmotion (e.g., long-span bridges and tall buildings)
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Evaluation of liquefaction triggering potential in Italy: a seismic-hazard-based approach
Full text linkIn the present study, we analyze ground-motion hazard
maps and hazard disaggregation in order to define areas in Italy where
liquefaction triggering due to seismic activity can not be excluded. To this
end, we refer to the triggering criteria (not to be confused with
liquefaction susceptibility criteria, which essentially take into account
soil type and depth to groundwater) proposed by the Italian Guidelines for
Seismic Microzonation, which are described in the main body of the
paper. However, the study can be replicated in other countries that
adopt different criteria. The final goal is the definition of a screening
map for all of Italy that classifies sites in terms of liquefaction
triggering potential according to their seismic hazard level. The map, which
is referred to with the Italian acronym MILQ – Mappa del potenziale d'Innesco
della LiQuefazione (i.e., map of liquefaction triggering potential), and the
associated data are freely accessible at the following web address:
https://distav.unige.it/rsni/milq.php (last access: 28 April 2023). Our results can be useful to guide
land-use planners in deciding whether liquefaction is a hazard that needs to
be considered within the planning processes or not. Furthermore, they can
serve as a guide for recommending geological and geotechnical investigations
aimed at the evaluation of liquefaction hazards or, conversely, rule out
further studies with consequent savings in efforts and money.</p
New insights into long-period (>1 s) seismic amplification effects in deep sedimentary basins: A case of the po plain basin of Northern Italy
No full textThis study investigates and quantifies the influence of the shallower deposits (down to few hundreds of meters) of the Po Plain sedimentary basin (northern Italy) on the long-period component (i.e., 1 s < T < 3 s) of seismic groundmotion, inwhich amplification effects due to the soft sediments above seismic bedrock were observed.A new seismostratigraphic model of the shallow deposits of the entire basin is provided with an unprecedented detail by taking advantage of recently acquired geophysical data. The seismostratigraphic model is used to simulate the groundmotion amplification in the Po Plain bymeans of extensive 1D ground response analysis. Results are compared with seismic observations available at a number of sites equipped with borehole seismic stations, where earthquakes have been recorded both at the surface and at the seismic bedrock depth. Despite the general agreement with observations concerning the seismic resonance frequencies, our model may fail in capturing the amplitude of the actual seismic amplification of the basin in the long-period range. We observe that 3D basin effects related to surface waves generated at the edge of the basin may play a significant role in those zones where seismic hazard is controlled by distant sources. In these cases, 1Dmodeling leads to average underestimations of 30%, up to a maximum of 60%. The amplification functions need to be corrected for a basin-effects correction term, which in this case is provided by the ground-motion prediction equation of the study area. The corrected amplification functions agree with the empirical observations, overcoming the uneven distribution of the recording stations in strong-motion datasets. These results should be taken into account in future seismic microzonation studies in the Po Plain area, where the 1D approach is commonly adopted in ground response analyses, and in site-specific seismic hazard assessments aimed at the design of structures that are sensitive to the long-period component of seismic groundmotion (e.g., long-span bridges and tall buildings)
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