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251.
Vincent Perron Aurore Laurendeau Fabrice Hollender Pierre-Yves Bard Céline Gélis Paola Traversa Stéphane Drouet 《Bulletin of Earthquake Engineering》2018,16(6):2211-2225
Seismic signal windowing is the preliminary step for many analysis procedures in engineering seismology (standard spectral ratio, quality factor, general inversion techniques, etc.). Moreover a noise window is often necessary for the data quality control through the signal-to-noise verification. Selecting the noise window can be challenging when large heterogeneous datasets are considered, especially when they include short pre-event noise signals. This study proposes a fully automatic and configurable (i.e., with default parameters that can also be user-defined) algorithm to windowing the noise and the P, S, coda and full signal once the P-wave (T P ) and S-wave (T S ) first arrivals are known. An application example is given on a KiK-net dataset. A Matlab language implementation of this algorithm is proposed as an online resource. 相似文献
252.
Paola Traversa David Baumont Kévin Manchuel Emmanuelle Nayman Christophe Durouchoux 《Bulletin of Earthquake Engineering》2018,16(6):2169-2193
The estimation of the seismological parameters of historical earthquakes is a key step when performing seismic hazard assessment in moderate seismicity regions as France. We propose an original method to assess magnitude and depth of historical earthquakes using intensity data points. A flowchart based on an exploration tree (ET) approach allows to apply a consistent methodology to all the different configurations of the earthquake macroseismic field and to explore the inherent uncertainties. The method is applied to French test case historical earthquakes, using the SisFrance (BRGM, IRSN, EDF) macroseismic database and the intensity prediction equations (IPEs) calibrated in the companion paper (Baumont et al. Bull Earthq Eng, 2017). A weighted least square scheme allowing for the joint inversion of magnitude and depth is applied to earthquakes that exhibit a decay of intensity with distance. Two cases are distinguished: (1) a “Complete ET” is applied to earthquakes located within the metropolitan territory, while (2) a “Simplified ET” is applied to both, offshore and cross border events, lacking information at short distances but disposing of reliable data at large ones. Finally, a priori-depth-based magnitude computation is applied to ancient or poorly documented events, only described by single/sporadic intensity data or few macroseismic testimonies. Specific processing of “felt” testimonies allows exploiting this complementary information for poorly described earthquakes. Uncertainties associated to magnitude and depth estimates result from both, full propagation of uncertainties related to the original macroseismic information and the epistemic uncertainty related to the IPEs selection procedure. 相似文献
253.
Francesca Barbagallo Melina Bosco Edoardo M. Marino Pier Paolo Rossi Paola R. Stramondo 《地震工程与结构动力学》2017,46(7):1099-1119
In the world, many existing buildings with RC framed structure were designed according to old seismic standards and present structural deficiencies. Buckling Restrained Braces (BRBs) can be effective for seismic upgrading of these structures, as pointed out by many studies. Nevertheless, Eurocode 8 (EC8) does not provide any rules for design of BRBs. This lack represents a big obstacle for application of this seismic upgrading technique in Europe. For this reason, a method for the design of seismic upgrading interventions by BRBs is proposed in this paper. The method is obtained as the best between two variants developed, investigated and compared in this paper. Based on a numerical investigation, the parameters that control the design method are calibrated to ensure the fulfillment of the Near Collapse performance objective stipulated in EC8. Finally, the capability of the proposed design method in fulfilling also performance objectives not explicitly considered in design is investigated. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
254.
Michela?CamelettiEmail author Valerio?De Rubeis Clarissa?Ferrari Paola?Sbarra Patrizia?Tosi 《Stochastic Environmental Research and Risk Assessment (SERRA)》2017,31(7):1593-1602
Seismic intensity, measured through the Mercalli–Cancani–Sieberg (MCS) scale, provides an assessment of ground shaking level deduced from building damages, any natural environment changes and from any observed effects or feelings. Generally, moving away from the earthquake epicentre, the effects are lower but intensities may vary in space, as there could be areas that amplify or reduce the shaking depending on the earthquake source geometry, geological features and local factors. Currently, the Istituto Nazionale di Geofisica e Vulcanologia analyzes, for each seismic event, intensity data collected through the online macroseismic questionnaire available at the web-page www.haisentitoilterremoto.it. Questionnaire responses are aggregated at the municipality level and analyzed to obtain an intensity defined on an ordinal categorical scale. The main aim of this work is to model macroseismic attenuation and obtain an intensity prediction equation which describes the decay of macroseismic intensity as a function of the magnitude and distance from the hypocentre. To do this we employ an ordered probit model, assuming that the intensity response variable is related through the link probit function to some predictors. Differently from what it is commonly done in the macroseismic literature, this approach takes properly into account the qualitative and ordinal nature of the macroseismic intensity as defined on the MCS scale. Using Markov chain Monte Carlo methods, we estimate the posterior probability of the intensity at each site. Moreover, by comparing observed and estimated intensities we are able to detect anomalous areas in terms of residuals. This kind of information can be useful for a better assessment of seismic risk and for promoting effective policies to reduce major damages. 相似文献
255.
Ellen Wohl Gary Brierley Daniel Cadol Tom J. Coulthard Tim Covino Kirstie A. Fryirs Gordon Grant Robert G. Hilton Stuart N. Lane Francis J. Magilligan Kimberly M. Meitzen Paola Passalacqua Ronald E. Poeppl Sara L. Rathburn Leonard S. Sklar 《地球表面变化过程与地形》2019,44(1):4-26
Connectivity describes the efficiency of material transfer between geomorphic system components such as hillslopes and rivers or longitudinal segments within a river network. Representations of geomorphic systems as networks should recognize that the compartments, links, and nodes exhibit connectivity at differing scales. The historical underpinnings of connectivity in geomorphology involve management of geomorphic systems and observations linking surface processes to landform dynamics. Current work in geomorphic connectivity emphasizes hydrological, sediment, or landscape connectivity. Signatures of connectivity can be detected using diverse indicators that vary from contemporary processes to stratigraphic records or a spatial metric such as sediment yield that encompasses geomorphic processes operating over diverse time and space scales. One approach to measuring connectivity is to determine the fundamental temporal and spatial scales for the phenomenon of interest and to make measurements at a sufficiently large multiple of the fundamental scales to capture reliably a representative sample. Another approach seeks to characterize how connectivity varies with scale, by applying the same metric over a wide range of scales or using statistical measures that characterize the frequency distributions of connectivity across scales. Identifying and measuring connectivity is useful in basic and applied geomorphic research and we explore the implications of connectivity for river management. Common themes and ideas that merit further research include; increased understanding of the importance of capturing landscape heterogeneity and connectivity patterns; the potential to use graph and network theory metrics in analyzing connectivity; the need to understand which metrics best represent the physical system and its connectivity pathways, and to apply these metrics to the validation of numerical models; and the need to recognize the importance of low levels of connectivity in some situations. We emphasize the value in evaluating boundaries between components of geomorphic systems as transition zones and examining the fluxes across them to understand landscape functioning. © 2018 John Wiley & Sons, Ltd. 相似文献
256.
Paola Gianguzza Fabio Badalamenti Fabrizio Gianguzza Chiara Bonaviri & Silvano Riggio 《Marine Ecology》2009,30(1):125-132
We investigated, with a series of field and laboratory observations, the possible effect of the starfish Marthasteria glacialis predation on the operational sex ratio (OSR), i.e. the number of sexually mature males divided by the total number of sexually mature adults of both sexes at any one time, of the edible sea urchin Paracentrotus lividus . The OSR was estimated three times during the sea urchin summer spawning period (July 2004, June 2005 and July 2006) on barren substrates of Ustica Island Marine Protected Area (Southern Tyrrhenian Sea, Italy). Four sites were selected: two characterized by high M. glacialis density (take zone C) and two controls with low starfish density (no-take zone A). Mature sea urchins were independently collected by SCUBA diving and sexed. The adult sex ratio was skewed towards males at high M. glacialis density sites, whereas it was balanced (1:1) at predator low-density sites. Results of sex-selective feeding experiments in the laboratory showed that females of P. lividus were more vulnerable to M. glacialis predation. These outcomes underline the possible importance of M. glacialis in regulating the OSR of P. lividus populations. 相似文献
257.
Mauro Celussi Alessandro Paoli Erica Crevatin Andrea Bergamasco Francesca Margiotta Vincenzo Saggiomo Serena Fonda Umani Paola Del Negro 《Estuarine, Coastal and Shelf Science》2009,81(4):491-500
During the 2006 Italian Antarctic expedition a diel sampling was performed close to Cape Hallett (Ross Sea) during the Austral summer. Under-ice seawater samples (4 m) were collected every 2 h for 28 h in order to estimate prokaryotic processes' variability and community structure dynamics. Prokaryotic and viral abundances, exoenzymatic activities (β-glucosidase, chitinase, lipase, alkaline phosphatase and leucine aminopeptidase), prokaryotic carbon production (3H-leucine incorporation) and community structure (Denaturing Gradient Gel Electrophoresis – DGGE fingerprints) were analysed. Results showed that the diel variability of the prokaryotic activity followed a variation in salinity, probably as a consequence of the periodical thawing of sea ice (driven by solar radiation and air temperature cycles), while negligible variation in viral and prokaryotic abundances occurred. The Bacterial and Archaeal community structures underwent an Operational Taxonomic Units (OTUs) temporal shift from the beginning to the end of the sampling, while Flavobacteria-specific primers highlighted high variations in this group possibly related to sea ice melting and substrate release. 相似文献
258.
259.
260.
Mary Loli Martínez-Aldama Paola Marziani Deborah Dultzin Jack W. Sulentic Alessandro Bressan Yang Chen Giovanna M. Stirpe 《Journal of Astrophysics and Astronomy》2015,36(4)
We present a new spectroscopic sample of 11 quasars at intermediate redshift observed with the Infrared Spectrometer and Array Camera (ISAAC) on the ESO Very Large Telescope (VLT), covering O i λ8446 and the Ca ii triplet 8498, 8542, 8662. The new observations – that supplement the sample presented by Martínez-Aldama et al. (2015) – allow us to confirm the constraints on physical conditions and location of the region emitting the low ionization lines, as well as the relation between Ca ii and Fe ii. 相似文献