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Rockfall seismic features analysis based on in situ tests:frequency, amplitude, and duration

Journal of Mountain Science 2019年第5期16卷 955-973页

作者： Liang FENG Veronica PAZZI Emanuele INTRIERI Teresa GRACCHI giovanni gigli Department of Earth Sciences University of Florence

In the seismic event classification,determining the seismic features of rockfall is significantly important for the automatic classification of seismic events because of the huge amount of raw data recorded by seismic stations in continuous monitoring. At the same time, the rockfall seismic features are still not completely *** study concentrates on the rockfall frequency content, amplitude(ground velocity), seismic waveform and duration analysis, of an artificial rockfall test at Torgiovannetto(a former quarry in Central Italy). A total of 90 blocks were released in the test, and their seismic signals and moving trajectories were recorded by four tri-axial seismic stations and four cameras, respectively. In the analysis processing,all the artificial rockfall signal traces were cut separately and the seismic features were extracted individually and automatically. In this study, the relationships between a) frequency content and impacted materials, b) frequency content and the distance between block releasing position and seismic station(source-receiver distance) were discussed. As a result, we found that the frequency content of rockfall focuses on 10-60 Hz and 80-90 Hz within a source-receiver distance of 200 m, and it is well correlated with impacted material and source-receiver distance. To evaluate the difference between earthquake and rockfall, 23 clear earthquake signals recorded in a seven month-long continuous seismic monitoring, carried out with the four seismic stations, were picked out, according to the Italian national earthquakes database(INGV). On these traces we performed the same analysis as in the artificial rockfall traces, and two parameters were defined to separate rockfall events from earthquake noise. The first one, the amplitude ratio, is related to the amplitude variation of rockfall between two stations and is greater than that of earthquakes, because of the higher attenuation occurring for rockfall events, which consists in high

关键词： Rockfall Seismic noise analysis Fourier transform Seismic events classification Time-series analysis Seismic monitoring

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Rockfall localization from seismic polarization considering multiple triaxial geophones and frequency bands

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Journal of Mountain Science 2020年第7期17卷 1541-1552页

作者： Liang FENG Veronica PAZZI Emanuele INTRIERI Teresa GRACCHI giovanni gigli Grazia TUCCI Department of Earth Sciences University of FlorenceVia G.La Pira 450121FlorenceItaly Department of Civil and Environment Engineering University of FlorenceVia Santa Marta 350139FlorenceItaly

Boulder/rock mass movements generate ground vibrations that can be recorded by geophone ***,there are two methods applied to rockfall trajectory reconstruction or rockfall seismic *** method uses seismic wave arrival times and is achieved by minimizing the differences in signal arrival times between multiple stations by grid map *** other method uses seismic polarization and is achieved by calculating eventsource back azimuths from the seismic polarizations of rockfall *** this study,we proposed the use of an overdetermined matrix for joint localization based on the polarization *** overdetermined matrix considers the contributions of all geophones in the network,and at each geophone is assigned a different weight according to the recorded signal qualities and the reliability of the calibrated back *** method shows a great advantage relative to the case in which only two sensors are ***,we suggested three marker parameters for proper frequency band selection in back azimuth calculations:energy,rectilinearity,and a special permanent frequency band(SPF).We found that the back azimuths calculated with energy and an SPF are generally close to the real back azimuths measured in the field,while the SPF is limited by seismic attenuation due to a long-distance *** localization results of rockfalls were validated by using field camera videos and in situ *** typical cases and 43 artificially released rockfalls are presented in this *** proposed method provides an interesting way to locate rockfall events and track rockfall trajectories and avoids the difficulties of obtaining accurate arrival times,as required by the arrival times method.

关键词： Rockfall Localization Seismic polarization Seismic monitoring Early warning

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Event Scenario Analysis for the Design of Rockslide Countermeasures

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Journal of Mountain Science 2014年第6期11卷 1521-1530页

作者： gigli giovanni INTRIERI Emanuele LOMBARDI Luca NOCENTINI Massimiliano FRODELLA William BALDUCCI Marco VENANTI Luca Domenico CASAGLI Nicola Department of Earth Science University of Studies of Florence Area Progetto Associati Studio Geologi Associati

The Torgiovannetto quarry(Assisi municipality,central Italy) is an example of a site where the natural equilibrium was altered by human activity,causing current slope instability phenomena which threaten two roadways important for the local *** quarry front,having a height of about 140 m,is affected by a 182,000 m3 rockslide developed in intensely fractured limestone and is too large to be *** 2003 some tension cracks were detected in the vegetated area above the quarry upper *** then on,several monitoring campaigns were carried out by means of different instrumentations(topographic total station,extensometers,inclinometers,ground-based interferometric radar,laser scanner and infrared thermal camera),allowing researchers to accurately define the landslide area and *** latter's major displacements are localized in the eastern *** deformational field appears to be related to the seasonal *** landslide hazard associated with the worst case scenario was evaluated in terms of magnitude,intensity and triggering *** the definition of the possible runout process the DAN 3D code was *** simulation results were used in order to design and construct a retaining ***,in order to preserve both the safety of the personnelinvolved in its realization and of the roadways users,an early warning system was *** early warning system is based on daily-averaged displacement velocity *** alarm level is reached if the prediction based on the methods of Saito(1969) and Fukuzono(1985) forecasts an imminent rupture.

关键词： Risk scenarios Risk management Landslides Monitoring Rock avalanche

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Landslide Characterization Using Satellite Interferometry (PSI), Geotechnical Investigations and Numerical Modelling: The Case Study of Ricasoli Village (Italy)

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International Journal of Geosciences 2013年第5期4卷 904-918页

作者： Ascanio Rosi Pietro Vannocci Veronica Tofani giovanni gigli Nicola Casagli Department of Earth Sciences University of Florence Florence Italy

Ricasoli is a village located in a morphological high in the Upper Arno river Valley (Tuscany), an area historically subject to widespread slope instability phenomena. This morphological high and the surrounding slopes result to be affected by numerous landslides, which cause the retreat of the escarpments surrounding the village, involving infrastructures and buildings. To better understand the behaviour of these phenomena a complete characterization, in terms of kinematics, mechanical properties and triggering conditions, of the landslides has been carried out. With this aim several boreholes, equipped both with inclinometer and piezometers, have been drilled and a number of samples have been collected and analysed. In addition to the traditional analysis, the radar satellite interferometry has been used to evaluate the evolution of the landslides and its correlation with rainfalls;furthermore a finite difference numerical modelling has been carried out to investigate the kinematics of the landslides and the deformation pattern.

关键词： Landslide Geotechnical Characterization Interferometry PSInSAR

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结合先进监测与数值模拟技术的滑坡完整风险隋况分析——意大利佛罗伦萨Beni山研究实例

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水文地质工程地质技术方法动态 2012年第3期 8-22页

作者： giovanni gigli 赵玉军(翻译) 孙建平(校对) Department of Earth Sciences University of Florence Largo Enrico Fermi 2 Arcetri 50125 Florence Italy 不详

2002年12月28日，在意大利佛罗伦萨Beni山脉东侧边坡发生了滑坡事件。在该边坡区域内，节理玄武岩和蛇绿质角砾岩上覆于中生代石灰岩（Calcaria Calpionelle组）。在崩塌发生前出现多种先兆信号：边坡变形发育是最主要的先兆信号；而且... 详细信息

2002年12月28日，在意大利佛罗伦萨Beni山脉东侧边坡发生了滑坡事件。在该边坡区域内，节理玄武岩和蛇绿质角砾岩上覆于中生代石灰岩（Calcaria Calpionelle组）。在崩塌发生前出现多种先兆信号：边坡变形发育是最主要的先兆信号；而且，边坡变形分析是风险情况评价的起点。实际上，在突发时期（开始于2002年4月13日）管理期间，我们通过结合地质力学调查、实验室分析、岩土工程调查、地球物理调查（地震和GBInSAR）、监测系统（去分光光度（distometric）系统和自动系统）和离散元数值模拟获得的数据，力求评估滑坡的实际延展情况、滑坡体范围内位移分布、滑坡体动力学特性及其时空演化。鉴于此，我们有望为政府当局提供所有所需信息以制定适当的滑坡风险管理与缓解措施。在滑坡事件发生后，我们采用滑程反分析法完成本项研究。这种方法主要针对于预期调查的成功与失败。

关键词：滑坡数值模拟监测 InSAR 破坏时间滑程

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Thermodynamics and dielectric response of BaTiO_(3)by data-driven modeling

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npj Computational Materials 2022年第1期8卷 1998-2014页

作者： Lorenzo gigli Max Veit Michele Kotiuga giovanni Pizzi Nicola Marzari Michele Ceriotti Laboratory of Computational Science and Modeling(COSMO) Institute of MaterialsÉcole Polytechnique Fédérale de LausanneCH-1015LausanneSwitzerland Theory and Simulation of Materials(THEOS)and National Centre for Computational Design and Discovery of Novel Materials(MARVEL) École Polytechnique Fédérale de LausanneCH-1015LausanneSwitzerland

Modeling ferroelectric materials from first principles is one of the successes of density-functional theory and the driver of much development effort,requiring an accurate description of the electronic processes and the thermodynamic equilibrium that drive the spontaneous symmetry breaking and the emergence of macroscopic *** demonstrate the development and application of an integrated machine learning model that describes on the same footing structural,energetic,and functional properties of barium titanate(BaTiO_(3)),a prototypical *** model uses ab initio calculations as a reference and achieves accurate yet inexpensive predictions of energy and polarization on time and length scales that are not accessible to direct ab initio *** predictions allow us to assess the microscopic mechanism of the ferroelectric *** presence of an order-disorder transition for the Ti off-centered states is the main driver of the ferroelectric transition,even though the coupling between symmetry breaking and cell distortions determines the presence of intermediate,partly-ordered ***,we thoroughly probe the static and dynamical behavior of BaTiO_(3)across its phase diagram without the need to introduce a coarse-grained description of the ferroelectric ***,we apply the polarization model to calculate the dielectric response properties of the material in a full ab initio manner,again reproducing the correct qualitative experimental behavior.

关键词： transition ferroelectric dielectric

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High-speed flow of interacting organic polaritons

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Light(Science & Applications) 2016年第1期5卷 235-240页

作者： giovanni Lerario Dario Ballarini Antonio Fieramosca Alessandro Cannavale Armando Genco Federica Mangione Salvatore Gambino Lorenzo Dominici Milena De Giorgi Giuseppe gigli Daniele Sanvitto CNR NANOTEC-Istituto di Nanotecnologia Via Monteroni73100 LecceItaly Dipartimento di matematica e fisica‘Ennio De Giorgi’ Universitàdel Salento73100 LecceItaly

The strong coupling of an excitonic transition with an electromagnetic mode results in composite quasi-particles called exciton polaritons,which have been shown to combine the best properties of their individual components in semiconductor ***,the physics and applications of polariton flows in organic materials and at room temperature are still unexplored because of the poor photon confinement in such ***,we demonstrate that polaritons formed by the hybridization of organic excitons with a Bloch surface wave are able to propagate for hundreds of microns showing remarkable third-order nonlinear interactions upon high injection *** findings pave the way for the study of organic nonlinear light–matter fluxes and for a technologically promising route of the realization of dissipation-less on-chip polariton devices operating at room temperature.

关键词： optical nonlinearity organic materials polaritons surface waves 2D optics

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