1,720,990 research outputs found
Onsite Earthquake Early Warning: Predictive Models for Acceleration Response Spectra Considering Site Effects
No full textOnsite earthquake early warning (EEW) systems exploit predictive models relating fea- tures extracted over the P-wave window to S-wave ground-motion parameters. These models are usually calibrated considering recordings from multiple stations and combining datasets from different regions under the ergodic assumption. Here, we show that the local-site conditions can play a significant role in determining the performance of onsite EEW predictive models in terms of rates of false or missed alerts. Interestingly, if partially nonergodic models are implemented, as done in probabilistic seismic hazard analysis, the negative impact of local-site amplifications can be mitigated. We explore the influence of site effects for onsite EEW predictive models calibrated between the peak displacement (Pd ) and integral squared velocity (Iv2) measured over a 3 s P-wave window, and the accel- eration response spectra (RSA) at nine different periods T (T 0:1, 0.15, 0.2, 0.3, 0.5, 0.75, 1.0, 1.5, and 2.0 s). We consider 58 earthquakes with magnitudes between Mw 3.7 and 6.5, belonging to the 2016–2017 central Italy seismic sequence that have been recorded by 100 accelerometer stations at hypocentral distances lesser than 150 km. We implement a mixed-effects regression analysis to explore the variability of the ground motion in terms of RSA predicted at different sites by considering two different group levels: in the first, each station is considered separately; in the second, we consider the Eurocode 8 (EC8, 2004) soil classification. Considering a probabilistic alert decision module applied to data from two selected stations, we show that the predictive models including site effects provide more reliable alerts, reducing the false alarms from 2.6% to 0.53% and the missed alarms from 10.1% to 4.8%. The residuals analysis shows that including a site-specific random effect in the predictive model contributes to reducing the apparent aleatory variability, whereas grouping data by EC8 classification does not provide significant benefit for EEW purposes
Comparison of manual and automatic onset Time picking for local earthquake in North Eastern Italy.
No full textLinking crustal tomographic images and surface geology around the Giudicarie and Schio-Vicenza fault systems (Southern Alps, Italy)
No full textGround shaking scenarios at the town of Vicoforte, Italy
No full textVicoforte is a small town in Northern Italy, which hosts a Cathedral with the world's largest elliptical dome. The name of the Basilica is “Regina Montis Regalis” and it is of extraordinary architectural and structural importance. The main objective of this study is the definition of the seismic hazard at the site of Vicoforte following a deterministic approach. Although Vicoforte is located in an area of moderate seismicity, the calculation of the most unfavourable seismic ground shaking scenarios is of great interest due to the importance of the Basilica and its vulnerability to even a moderate seismic excitation.
The closest active faults to Vicoforte were identified in order to simulate the potentially most severe ground shaking scenarios compatibly with the tectonic and seismic setting of the region. Subsequently, numerical simulations were conducted through finite faults numerical models using two different approaches: the extended kinematic source model of Hisada and Bielak and the stochastic method of Motazedian and Atkinson. They, respectively, simulate the low and high frequency ranges of predicted ground motion. The numerical models used for the simulations were calibrated by a comparison between synthetic results and recorded data. A parametric study was finally carried out to identify the most critical fault rupture mechanisms
Structure and properties of the Adriatic crust in the central-eastern Southern Alps (Italy) from local earthquake tomography
No full textStructure and properties of the Adriatic crust were determined
from local earthquake tomography around the Giudicarie
fault zone (central-eastern Southern Alps, Italy).
Tomographic results, based on well-suited 436 revised earthquakes
(period 1994–2007), have a resolution comparable to
the scale of regional geological domains and tectonic structures.
The observed strong velocity anomalies correlate well
with lithological variations corresponding to different
geological domains (particularly magmatic complexes at
depth) and with high fracturing and/or presence of fluids
along active fault systems (South Giudicarie and Valsugana–
Bassano del Grappa–Montello thrusts)
Crustal structure, seismicity and seismotectonics of the Trentino region (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
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
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