1,720,997 research outputs found
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
A new approach for a fully automated earthquake monitoring: the local seismic network of the Trentino region (NE Italy)
No full textAn application of the Complete Automatic Seismic Processor (CASP) for seismic monitoring is presented. Its integrated and iterative fully automatic procedure is able to achieve complete data analysis and significantly rapid elaborations. Its performance in real-time seismic monitoring and alerting is tested in the Trentino region (NE Italy) for the period 1st March 2018 – 31st August 2019. CASP precisely and accurately located 386 seismic events, with local magnitudes in the -0.8–3.4 range, and produced a seismic catalogue with a magnitude of completeness around 1.1. Automatic earthquake solutions, with average horizontal and vertical errors of 1.1 and 1.5 km, are very similar to those included in a manually revised reference catalogue. In addition, 146 detected events are located in the area of the local porphyry quarries. CASP alerts are delivered as Short Message Service (SMS), Telegram and e-mail messages within an average time of just over two minutes from the earthquake origin time. These alerts contain earthquake source parameters, ground shaking levels and instrumental intensities. CASP reliability, promptness and robustness permit to civil protection and decision makers to perform a monitoring primarily dedicated to emergency management, in order to evaluate both seismic sources and their effects (peak ground acceleration) at local targets, such as more inhabited territories and critical infrastructures (dams and hydropower plants)
Linking crustal tomographic images and surface geology around the Giudicarie and Schio-Vicenza fault systems (Southern Alps, Italy)
No full text
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
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Impact of magnitude selection on aleatory variability associated with ground-motion prediction equations: Part I—local, energy, and moment magnitude calibration and stress-drop variability in central Italy
No full textIn this study, we analyzed 10 yrs of seismicity in central Italy from 2008 to 2017, a period witnessing more than 1400 earthquakes in the magnitude range 2.5≤Mw≤6.5. The data set includes the main sequences that have occurred in the area, including those associated with the 2009 Mw 6.3 L'Aquila earthquake and the 2016–2017 sequence (Mw 6.2 Amatrice, Mw 6.1 Visso, and Mw 6.5 Norcia earthquakes). We calibrated a local magnitude scale, investigating the impact of changing the reference distance at which the nonparametric attenuation is tied to the zero‐magnitude attenuation function for southern California. We also developed an attenuation model to compute the radiated seismic energy (Es) from the time integral of the squared ground‐motion velocity. Seismic moment (M0) and stress drop (Δσ) were estimated for each earthquake by fitting a ω‐square model to the source spectra obtained by applying a nonparametric spectral inversion. The Δσ‐values vary over three orders of magnitude from about 0.1 to 10 MPa, the larger values associated with the mainshocks. The Δσ‐values describe a lognormal distribution with mean and standard deviation equal to log(Δσ)=(−0.25±0.45) (i.e., the mean Δσ is 0.57 MPa, with a 95% confidence interval from 0.08 to 4.79 MPa). The Δσ variability introduces a spread in the distribution of seismic energy versus moment, with differences in energy up two orders of magnitudes for earthquakes with the same moment. The variability in the high‐frequency spectral levels is captured by the local magnitude (ML), which scales with radiated energy as ML=(−1.59+0.52logEs) for logEs≤10.26 and ML=(−1.38+0.50logEs) otherwise. As the peak ground velocity increases with increasing Δσ, local and energy magnitudes perform better than moment magnitude as predictors for the shaking potential. The availability of different magnitude scales and source parameters for a large earthquake population will help characterize the between‐event ground‐motion variability in central Italy
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
The RAMONES service for rapid assessment of seismic moment and radiated energy in central Italy: Concepts, capabilities, and future perspectives
No full textWe present Rapid Assessment of MOmeNt and Energy Service (RAMONES), a service for disseminating through a web interface, the estimates of seismic moment (M0) and radiated energy (ER) for earthquakes occurring in central Italy with local magnitudes above 1.7. The service is based on a fully-Automatic procedure developed for downloading and processing open seismological data from the European Integrated Data Archive, Italian Civil Protection repository, and Incorporated Research Institutions for Seismology (IRIS). In its actual configuration, RAMONES uses the seismic catalog generated through the event webservice of the Italian Institute of Geophysics and Volcanology (compliant with International Federation of Digital Seismograph Networks standards) to guide the data download. The concept of RAMONES is to estimate M0 and ER from features extracted directly from recordings, namely the S-wave peak displacement (PDS) and the integral of the squared velocity (IV2S) evaluated over the S-wave window at local distances. A data set composed of 6515 earthquakes recorded in central Italy between 2008 and 2018 was used to calibrate the attenuation models relating M0 to PDS and ER to IV2S, including station corrections. The calibration values for M0 and ER were extracted from the source spectra obtained by applying a decomposition approach to the Fourier amplitude spectra known as the generalized inversion technique. To test the capabilities of RAMONES, we validate the attenuation models by performing residual analysis over about 60 earthquakes occurring in 2019 that were used for the spectral decomposition analysis but not considered in the calibration phase. Since January 2020, a testing operational phase has been running, and RAMONES has analyzed about 800 earthquakes by September 2020. The distribution of the source parameters and their relevant scaling relationships are automatically computed and disseminated in the form of maps, parametric tables, figures, and reports available through the RAMONES web interface
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