The Experts below are selected from a list of 324 Experts worldwide ranked by ideXlab platform
Giuliano Francesco Panza - One of the best experts on this subject based on the ideXlab platform.
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simulation of the 2009 mw 4 tehran earthquake using a hybrid method of Modal Summation and finite difference
Journal of Geophysics and Engineering, 2013Co-Authors: Vahid Gholami, Giuliano Francesco Panza, Franco Vaccari, H Hamzehloo, Mohamad Reza GhayamghamianAbstract:The Greater Tehran Area is the most important city of Iran and hosts about 20% of the country?s population. Despite the presence of major faults and the occurrence of historical earthquakes, the seismicity is relatively low at present. Thus, it is important to estimate the ground motion for preventive, reliable seismic hazard assessment. An earthquake with magnitude Mw = 4, which occurred close to Tehran, 17 October 2009, is the first local earthquake that has been recorded by the local strong ground motion network in Tehran. To simulate the ground motion caused by the earthquake a hybrid technique is used. It combines two methods: the analytical Modal Summation and the numerical finite difference, taking advantage of the merits of both. The Modal Summation is applied to simulate wave propagation from the source to the sedimentary basin and finite difference to propagate the incoming wavefield in the laterally heterogeneous part of the structural model that contains the sedimentary basin. Synthetic signals are simulated along two East?West and Southeast?Northwest profiles. Frequency, response spectra, and time domain, waveforms and peak values, parameters are computed synthetically and compared with observed records. Results show agreement between observed and simulated signals. The simulation shows local site amplification as high as 6 in the southern part of Tehran.
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Simulation of the 2009, Mw = 4 Tehran earthquake using a hybrid method of Modal Summation and finite difference
Journal of Geophysics and Engineering, 2013Co-Authors: Vahid Gholami, Franco Vaccari, H Hamzehloo, Mohamad Reza Ghayamghamian, Giuliano Francesco PanzaAbstract:The Greater Tehran Area is the most important city of Iran and hosts about 20% of the country?s population. Despite the presence of major faults and the occurrence of historical earthquakes, the seismicity is relatively low at present. Thus, it is important to estimate the ground motion for preventive, reliable seismic hazard assessment. An earthquake with magnitude Mw = 4, which occurred close to Tehran, 17 October 2009, is the first local earthquake that has been recorded by the local strong ground motion network in Tehran. To simulate the ground motion caused by the earthquake a hybrid technique is used. It combines two methods: the analytical Modal Summation and the numerical finite difference, taking advantage of the merits of both. The Modal Summation is applied to simulate wave propagation from the source to the sedimentary basin and finite difference to propagate the incoming wavefield in the laterally heterogeneous part of the structural model that contains the sedimentary basin. Synthetic signals are simulated along two East?West and Southeast?Northwest profiles. Frequency, response spectra, and time domain, waveforms and peak values, parameters are computed synthetically and compared with observed records. Results show agreement between observed and simulated signals. The simulation shows local site amplification as high as 6 in the southern part of Tehran.
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Three-Dimensional Seismic Wave Propagation by Modal Summation: Method and Validation
Pure and Applied Geophysics, 2011Co-Authors: C. La Mura, Fabio Romanelli, T. B. Yanovskaya, Giuliano Francesco PanzaAbstract:It is an acquired result that, in order to enable realistic earthquake hazard assessment and reliable estimation of the ground motion response to an earthquake, three-dimensional velocity models have to be considered. In this paper we present a new analytical procedure for determining the seismic wavefield in a 3D anelastic model based on the combination of the ray theory with the Modal Summation method. The proposed procedure has been validated by considering the three-dimensional model of the Kanto basin (Japan) available in the literature. Three-dimensional simulations were performed for the 1990 Odawara earthquake. The results obtained were compared both with recorded signals and with simulations available in the literature for several stations located within the Kanto basin. Besides the advantage of being a useful tool for assessment of seismic hazard and seismic risk reduction, it is characterized by high efficiency, in fact, once the study region is identified and the 3D model is constructed, the computation, at each station, of the three components of the synthetic signal (displacement, velocity, and acceleration) takes less than 3 h on a 2 GHz CPU.
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An approach of Microzonation of the Sofia city
Acta Geodaetica et Geophysica Hungarica, 2008Co-Authors: G. Koleva, E. Zuccolo, I. Paskaleva, F. Vaccari, Giuliano Francesco PanzaAbstract:The city of Sofia has the densest population of Bulgaria — around 1.27 million people. The capital is exposed to high seismic risk. According to the Bulgarian seismic code, Sofia has been included in a seismic category characterized by intensity IX (MSK), which corresponds to a horizontal acceleration of 0.27 g for the anchoring of the elastic response spectrum. Because of the lack of instrumental seismic data, realistic synthetic strong motion waveforms for two opposite positions of seismic sources, have been generated for an expected earthquake scenarios ( M = 7) along three geological profiles. A hybrid modeling method has been used for the modeling, which is based on the Modal Summation technique and finite difference scheme. The calculation has been done using an extended source model. The site effect is represented in terms of response spectra ratio (RSR), with respect to a bedrock model. The three components synthetic seismograms, computed in the domain of displacement, velocity and acceleration have been processed to extract some parameters very useful for engineering applications.
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realistic modelling of waveforms in laterally heterogeneous anelastic media by Modal Summation
Geophysical Journal International, 2000Co-Authors: Fabio Romanelli, Giuliano Francesco Panza, Franco VaccariAbstract:For urban areas where numerical modelling has been successfully compared with strong motion records, the theoretical computations of synthetic seismograms permit a detailed microzoning based on a set of possible earthquake scenarios. For areas where very limited recordings are available, the synthetic time series can be used to estimate the expected ground motion, thus leading to a pre-disaster microzonation without the need to wait for an earthquake to occur. In both cases the use of synthetic computations is necessary to overcome the fact that the so-called local site effects can be strongly dependent on the properties of the seismic source generating the seismic input. In the framework of UNESCO-IUGS-IGCP project 414, ‘Realistic Modelling of Seismic Input for Megacities and Large Urban Areas’, two deterministic approaches have been applied to several urban areas for the purpose of seismic microzoning. The two approaches, valid for anelastic media, are the hybrid technique, based on the Modal-Summation technique and finite differences, and the mode-coupling analytical technique. We show three examples of the application of the deterministic techniques for seismic hazard assessment at urban scale, discussing the results for the cities of Rome, Catania and Augusta (Italy). The data set of synthetic seismograms can be fruitfully used and analysed by civil engineers for design and reinforcement actions, and therefore supplies a particularly powerful, and economical, tool for the prevention aspects of Civil Defence.
Franco Vaccari - One of the best experts on this subject based on the ideXlab platform.
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simulation of the 2009 mw 4 tehran earthquake using a hybrid method of Modal Summation and finite difference
Journal of Geophysics and Engineering, 2013Co-Authors: Vahid Gholami, Giuliano Francesco Panza, Franco Vaccari, H Hamzehloo, Mohamad Reza GhayamghamianAbstract:The Greater Tehran Area is the most important city of Iran and hosts about 20% of the country?s population. Despite the presence of major faults and the occurrence of historical earthquakes, the seismicity is relatively low at present. Thus, it is important to estimate the ground motion for preventive, reliable seismic hazard assessment. An earthquake with magnitude Mw = 4, which occurred close to Tehran, 17 October 2009, is the first local earthquake that has been recorded by the local strong ground motion network in Tehran. To simulate the ground motion caused by the earthquake a hybrid technique is used. It combines two methods: the analytical Modal Summation and the numerical finite difference, taking advantage of the merits of both. The Modal Summation is applied to simulate wave propagation from the source to the sedimentary basin and finite difference to propagate the incoming wavefield in the laterally heterogeneous part of the structural model that contains the sedimentary basin. Synthetic signals are simulated along two East?West and Southeast?Northwest profiles. Frequency, response spectra, and time domain, waveforms and peak values, parameters are computed synthetically and compared with observed records. Results show agreement between observed and simulated signals. The simulation shows local site amplification as high as 6 in the southern part of Tehran.
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Simulation of the 2009, Mw = 4 Tehran earthquake using a hybrid method of Modal Summation and finite difference
Journal of Geophysics and Engineering, 2013Co-Authors: Vahid Gholami, Franco Vaccari, H Hamzehloo, Mohamad Reza Ghayamghamian, Giuliano Francesco PanzaAbstract:The Greater Tehran Area is the most important city of Iran and hosts about 20% of the country?s population. Despite the presence of major faults and the occurrence of historical earthquakes, the seismicity is relatively low at present. Thus, it is important to estimate the ground motion for preventive, reliable seismic hazard assessment. An earthquake with magnitude Mw = 4, which occurred close to Tehran, 17 October 2009, is the first local earthquake that has been recorded by the local strong ground motion network in Tehran. To simulate the ground motion caused by the earthquake a hybrid technique is used. It combines two methods: the analytical Modal Summation and the numerical finite difference, taking advantage of the merits of both. The Modal Summation is applied to simulate wave propagation from the source to the sedimentary basin and finite difference to propagate the incoming wavefield in the laterally heterogeneous part of the structural model that contains the sedimentary basin. Synthetic signals are simulated along two East?West and Southeast?Northwest profiles. Frequency, response spectra, and time domain, waveforms and peak values, parameters are computed synthetically and compared with observed records. Results show agreement between observed and simulated signals. The simulation shows local site amplification as high as 6 in the southern part of Tehran.
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DETERMINISTIC SEISMIC GROUND MOTION MODELLING OF THE GREATER ACCRA METROPOLITAN AREA, SOUTHEASTERN GHANA
South African Journal of Geology, 2009Co-Authors: P.e. Amponsah, Giuliano F. Panza, B.k. Banoeng-yakubo, Franco VaccariAbstract:The seismic ground motion of the greater Accra Metropolitan Area has been modelled for land use planning and disaster mitigation. The deterministic computation, a hybrid method based on the Modal Summation and finite difference method was used. Using these techniques, the seismic ground motion along four profiles located in the metropolis has been computed. The 1939 earthquake of magnitude 6.5 (ML ) was used as the scenario earthquake. Synthetic seismic waveforms from which parameters for engineering design such as peak ground acceleration, velocity and spectral amplifications have been produced along the geological cross sections. The peak ground acceleration and velocity computed for the metropolis ranges from 0.14 g to 0.57 g and 9.2 cms−1 to 37.1 cms−1, respectively. These correspond to intensity ranging from VII to IX on the Modified Mercalli Intensity scale. Areas in the metropolis underlain by unconsolidated sediments experience the largest shakings. The results illustrated represent a useful guide for civil engineers in the design of buildings in the metropolis for safe and sustainable development.
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Realistic Ground Motion Scenarios: Methodological Approach
AIP Conference Proceedings, 2008Co-Authors: C. Nunziata, Fabio Romanelli, Franco Vaccari, Antonella Peresan, E. Zuccolo, Giuliano F. PanzaAbstract:The definition of realistic seismic input can be obtained from the computation of a wide set of time histories, corresponding to possible seismotectonic scenarios. The propagation of the waves in the bedrock from the source to the local laterally varying structure is computed with the Modal Summation technique, while in the laterally heterogeneous structure the finite difference method is used. The definition of shear wave velocities within the soil cover is obtained from the non‐linear inversion of the dispersion curve of group velocities of Rayleigh waves, artificially or naturally generated. Information about the possible focal mechanisms of the sources can be obtained from historical seismicity, based on earthquake catalogues and inversion of isoseismal maps. In addition, morphostructural zonation and pattern recognition of seismogenic nodes is useful to identify areas prone to strong earthquakes, based on the combined analysis of topographic, tectonic, geological maps and satellite photos. We show th...
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Seismicity, seismic input and site effects in the Sahel—Algiers region (North Algeria)
Soil Dynamics and Earthquake Engineering, 2007Co-Authors: Assia Harbi, Franco Vaccari, Giuliano F. Panza, Said Maouche, Abdelkrim Aoudia, F. Oussadou, D. BenouarAbstract:Abstract Algiers city is located in a seismogenic zone. To reduce the impact of seismic risk in this Capital city, a realistic modelling of the seismic ground motion (SGM) is conducted by using the hybrid method that combines the finite differences method and the Modal Summation. For this purpose, a complete database of geological, geophysical and earthquake data is constructed. A critical re-appraisal of the seismicity of the zone [2.25°E–3.50°E, 36.50°N–37.00°N] is performed and an earthquake list, for the period 1359–2002, is compiled. The analysis of existing and newly retrieved macroseismic information allowed the definition of earthquake parameters of macroseismic events for which a degree of reliability is assigned. Geological cross sections have been built up to model the SGM in the city, caused by the 1989 Mont-Chenoua and the 1924 Douera earthquakes. Synthetic seismograms and response spectral ratio is produced for Algiers, and they show that the soft sediments in Algiers centre are responsible of the noticed amplification of the SGM.
Fabio Romanelli - One of the best experts on this subject based on the ideXlab platform.
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Three-Dimensional Seismic Wave Propagation by Modal Summation: Method and Validation
Pure and Applied Geophysics, 2011Co-Authors: C. La Mura, Fabio Romanelli, T. B. Yanovskaya, Giuliano Francesco PanzaAbstract:It is an acquired result that, in order to enable realistic earthquake hazard assessment and reliable estimation of the ground motion response to an earthquake, three-dimensional velocity models have to be considered. In this paper we present a new analytical procedure for determining the seismic wavefield in a 3D anelastic model based on the combination of the ray theory with the Modal Summation method. The proposed procedure has been validated by considering the three-dimensional model of the Kanto basin (Japan) available in the literature. Three-dimensional simulations were performed for the 1990 Odawara earthquake. The results obtained were compared both with recorded signals and with simulations available in the literature for several stations located within the Kanto basin. Besides the advantage of being a useful tool for assessment of seismic hazard and seismic risk reduction, it is characterized by high efficiency, in fact, once the study region is identified and the 3D model is constructed, the computation, at each station, of the three components of the synthetic signal (displacement, velocity, and acceleration) takes less than 3 h on a 2 GHz CPU.
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Realistic Ground Motion Scenarios: Methodological Approach
AIP Conference Proceedings, 2008Co-Authors: C. Nunziata, Fabio Romanelli, Franco Vaccari, Antonella Peresan, E. Zuccolo, Giuliano F. PanzaAbstract:The definition of realistic seismic input can be obtained from the computation of a wide set of time histories, corresponding to possible seismotectonic scenarios. The propagation of the waves in the bedrock from the source to the local laterally varying structure is computed with the Modal Summation technique, while in the laterally heterogeneous structure the finite difference method is used. The definition of shear wave velocities within the soil cover is obtained from the non‐linear inversion of the dispersion curve of group velocities of Rayleigh waves, artificially or naturally generated. Information about the possible focal mechanisms of the sources can be obtained from historical seismicity, based on earthquake catalogues and inversion of isoseismal maps. In addition, morphostructural zonation and pattern recognition of seismogenic nodes is useful to identify areas prone to strong earthquakes, based on the combined analysis of topographic, tectonic, geological maps and satellite photos. We show th...
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A view to the intermediate-depth Vrancea earthquake of May 30, 1990 — Case study in NE Bulgaria
Acta Geodaetica et Geophysica Hungarica, 2004Co-Authors: M. Kouteva, I. Paskaleva, G. F. Panza, Fabio RomanelliAbstract:A deterministic analytical procedure for ground motion modelling, combining both Modal Summation and mode coupling techniques has been implemented to obtain synthetic seismic signals at Russe, NE Bulgaria, due to one of the strongest Vrancea intermediate-depth earthquakes, which occurred during the last century, May 30, 1990. The frequency content of the synthetic signals in different frequency ranges, up to 1 and 2 Hz, has been studied separately. The results of this study, i.e. time histories and related ground motions parameters, can be used for different earthquake engineering analyses, e.g. structural performance assessments.
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A VIEW TO THE INTERMEDIATE-DEPTH VRANCEA EARTHQUAKE OF MAY 30,1990 - CASE STUDY IN NE BULGARIA
Acta Geodaetica Et Geophysica Hungarica, 2004Co-Authors: M. Kouteva, I. Paskaleva, Giuliano F. Panza, Fabio RomanelliAbstract:A deterministic analytical procedure for ground motion modelling, combining both Modal Summation and mode coupling techniques has been implemented to obtain synthetic seismic signals at Russe, NE Bulgaria, due to one of the strongest Vrancea intermediate-depth earthquakes, which occurred during the last century, May 30, 1990. The frequency content of the synthetic signals in different frequency ranges, up to 1 and 2 Hz, has been studied separately. The results of this study, i.e. time histories and related ground motions parameters, can be used for different earthquake engineering analyses, e.g. structural performance assessments.
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applications of the Modal Summation technique to the theoretical site response estimation
Journal of Computational Acoustics, 2001Co-Authors: Fabio Romanelli, Franco Vaccari, G. F. PanzaAbstract:A practical definition of site effect, that accounts for both the seismological and engineering point of view, is the one given by Field7: "the unique behavior of a site, relative to other sites, that persists given all (or most) of the potential sources of earthquake ground motion in the region". This definition implicitly indicates the difficulties connected with a correct estimate (or prediction) of the site effect. We estimate theoretical site responses adopting several techniques and using different seismic motion types. Our results confirm that the identification of the site behavior with a set of resonance frequencies can be a very difficult task, especially when the amplification levels seem to be "azimuthally" dependent. We show that the adoption of simplified models can lead to misleading conclusions concerning the seismic response of sedimentary basins. The results suggest that, in order to perform an accurate estimate of the site effects in complicated geometries, it is necessary to make a parametric study that takes into account the complex combination of the source and propagation factors.
Giuliano F. Panza - One of the best experts on this subject based on the ideXlab platform.
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Hybrid MS-BIEM for Seismic Site-Response Phenomena: A Case Study of Sofia
Harmonization of Seismic Hazard in Vrancea Zone, 2020Co-Authors: Petia Dineva, C. La Mura, I. Paskaleva, Giuliano F. PanzaAbstract:The study presents and solves the 2-D elastodynamic model for seismic in-plane wave propagation in laterally inhomogeneous geological profiles imbedded in a vertically inhomogeneous half-space in which an earthquake source is buried. To this end, an efficient hybrid Modal Summation- boundary integral equation method (MSM-BIEM) is developed and applied. The MSM is used as a tool for simulating wave propagation from the source position to the multilayered laterally inhomogeneous geological profile where the BIEM is applied. The proposed model and the hybrid tool are used to investigate the phenomena of site effects. In fact, such a methodology has the potential to investigate the combined effects of different physical phenomena like surface topography, lateral inhomogeneity and the existence of water saturation in soils on the estimation of site effects. The model and hybrid computational tool developed are applied to contribute to the seismic risk analysis of the Bulgarian capital Sofia.
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DETERMINISTIC SEISMIC GROUND MOTION MODELLING OF THE GREATER ACCRA METROPOLITAN AREA, SOUTHEASTERN GHANA
South African Journal of Geology, 2009Co-Authors: P.e. Amponsah, Giuliano F. Panza, B.k. Banoeng-yakubo, Franco VaccariAbstract:The seismic ground motion of the greater Accra Metropolitan Area has been modelled for land use planning and disaster mitigation. The deterministic computation, a hybrid method based on the Modal Summation and finite difference method was used. Using these techniques, the seismic ground motion along four profiles located in the metropolis has been computed. The 1939 earthquake of magnitude 6.5 (ML ) was used as the scenario earthquake. Synthetic seismic waveforms from which parameters for engineering design such as peak ground acceleration, velocity and spectral amplifications have been produced along the geological cross sections. The peak ground acceleration and velocity computed for the metropolis ranges from 0.14 g to 0.57 g and 9.2 cms−1 to 37.1 cms−1, respectively. These correspond to intensity ranging from VII to IX on the Modified Mercalli Intensity scale. Areas in the metropolis underlain by unconsolidated sediments experience the largest shakings. The results illustrated represent a useful guide for civil engineers in the design of buildings in the metropolis for safe and sustainable development.
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Earthquakes site effects modeling by hybrid MS-BIEM: the case study of Sofia, Bulgaria
RENDICONTI LINCEI, 2009Co-Authors: Giuliano F. Panza, Petia Dineva, Ivanka Paskaleva, Cristina La MuraAbstract:The study solves 2D elastodynamic model for seismic in-plane wave propagation in laterally inhomogeneous geological profiles situated in a vertically inhomogeneous half-space with a seismic source. For the aim, an efficient hybrid Modal Summation-Boundary Integral Equation Method (MSM-BIEM) is applied. The MSM is used as a tool for the simulation of wave propagation from the source position to the local multilayered laterally inhomogeneous geological profile, where the BIEM is applied. The BIEM is based on the frequency-dependent fundamental solution of the governing equation in elastodynamics and the hybrid method works in the frequency domain. The inverse FFT solution is applied to obtain time histories. The hybrid tool is applied to several models for the investigation of local site effects due to: (a) the impedance contrasts between soil layers, (b) surface topography and lateral inhomogeneity, (c) the seismic source properties and (d) the existence of water saturation in soils. The application of the modeling tool is a contribution to the seismic risk analysis of Sofia city.
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Realistic Ground Motion Scenarios: Methodological Approach
AIP Conference Proceedings, 2008Co-Authors: C. Nunziata, Fabio Romanelli, Franco Vaccari, Antonella Peresan, E. Zuccolo, Giuliano F. PanzaAbstract:The definition of realistic seismic input can be obtained from the computation of a wide set of time histories, corresponding to possible seismotectonic scenarios. The propagation of the waves in the bedrock from the source to the local laterally varying structure is computed with the Modal Summation technique, while in the laterally heterogeneous structure the finite difference method is used. The definition of shear wave velocities within the soil cover is obtained from the non‐linear inversion of the dispersion curve of group velocities of Rayleigh waves, artificially or naturally generated. Information about the possible focal mechanisms of the sources can be obtained from historical seismicity, based on earthquake catalogues and inversion of isoseismal maps. In addition, morphostructural zonation and pattern recognition of seismogenic nodes is useful to identify areas prone to strong earthquakes, based on the combined analysis of topographic, tectonic, geological maps and satellite photos. We show th...
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Seismicity, seismic input and site effects in the Sahel—Algiers region (North Algeria)
Soil Dynamics and Earthquake Engineering, 2007Co-Authors: Assia Harbi, Franco Vaccari, Giuliano F. Panza, Said Maouche, Abdelkrim Aoudia, F. Oussadou, D. BenouarAbstract:Abstract Algiers city is located in a seismogenic zone. To reduce the impact of seismic risk in this Capital city, a realistic modelling of the seismic ground motion (SGM) is conducted by using the hybrid method that combines the finite differences method and the Modal Summation. For this purpose, a complete database of geological, geophysical and earthquake data is constructed. A critical re-appraisal of the seismicity of the zone [2.25°E–3.50°E, 36.50°N–37.00°N] is performed and an earthquake list, for the period 1359–2002, is compiled. The analysis of existing and newly retrieved macroseismic information allowed the definition of earthquake parameters of macroseismic events for which a degree of reliability is assigned. Geological cross sections have been built up to model the SGM in the city, caused by the 1989 Mont-Chenoua and the 1924 Douera earthquakes. Synthetic seismograms and response spectral ratio is produced for Algiers, and they show that the soft sediments in Algiers centre are responsible of the noticed amplification of the SGM.
G. F. Panza - One of the best experts on this subject based on the ideXlab platform.
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A view to the intermediate-depth Vrancea earthquake of May 30, 1990 — Case study in NE Bulgaria
Acta Geodaetica et Geophysica Hungarica, 2004Co-Authors: M. Kouteva, I. Paskaleva, G. F. Panza, Fabio RomanelliAbstract:A deterministic analytical procedure for ground motion modelling, combining both Modal Summation and mode coupling techniques has been implemented to obtain synthetic seismic signals at Russe, NE Bulgaria, due to one of the strongest Vrancea intermediate-depth earthquakes, which occurred during the last century, May 30, 1990. The frequency content of the synthetic signals in different frequency ranges, up to 1 and 2 Hz, has been studied separately. The results of this study, i.e. time histories and related ground motions parameters, can be used for different earthquake engineering analyses, e.g. structural performance assessments.
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Modelling of Seismic Ground Motion in Santiago de Cuba City from Earthquakes in Oriente Fault Seismic Zone
pure and applied geophysics, 2001Co-Authors: L. Alvarez, Franco Vaccari, G. F. Panza, B. E. GonzálezAbstract:— We present the results of complete P - SV and SH waves modelling, up to a maximum frequency of 1 Hz, along two profiles in Santiago de Cuba city. The seismic sources are located in the depth range from 10 to 40 km on the Oriente fault zone at distances of several tens of kilometres from the city. The calculation has been made by a hybrid method: Modal Summation in the regional anelastic model (one-dimensional) where the source is buried, and finite differences in the local sedimentary anelastic models (two-dimensional). The analysis of the influence of the depth and of the distance of the source on the site effects shows that standard traditional methods, based on the deconvolution analysis of the rock outcrop motion, can lead to erroneous results.
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Theoretical and Observed Depth Correction for M _ s
pure and applied geophysics, 2001Co-Authors: M. Herak, G. F. Panza, G. CostaAbstract:— Modal Summation technique is used to generate 5000, three-component theoretical seismograms of Love and Rayleigh waves, assuming modified PREM (PREM-C) and AK135F global earth models. The focal depth h and the geometrical fault parameters are randomly chosen so as to uniformly cover possible source mechanisms and obtain uniform distribution of log h in the interval 1
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applications of the Modal Summation technique to the theoretical site response estimation
Journal of Computational Acoustics, 2001Co-Authors: Fabio Romanelli, Franco Vaccari, G. F. PanzaAbstract:A practical definition of site effect, that accounts for both the seismological and engineering point of view, is the one given by Field7: "the unique behavior of a site, relative to other sites, that persists given all (or most) of the potential sources of earthquake ground motion in the region". This definition implicitly indicates the difficulties connected with a correct estimate (or prediction) of the site effect. We estimate theoretical site responses adopting several techniques and using different seismic motion types. Our results confirm that the identification of the site behavior with a set of resonance frequencies can be a very difficult task, especially when the amplification levels seem to be "azimuthally" dependent. We show that the adoption of simplified models can lead to misleading conclusions concerning the seismic response of sedimentary basins. The results suggest that, in order to perform an accurate estimate of the site effects in complicated geometries, it is necessary to make a parametric study that takes into account the complex combination of the source and propagation factors.
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Deterministic Seismic Zoning of Eastern Cuba
pure and applied geophysics, 1999Co-Authors: L. Alvarez, Franco Vaccari, G. F. PanzaAbstract:—A deterministic seismic zoning of Cuba is performed by modelling, with Modal Summation, the complete P-SV and SH waves fields generated by point-source earthquakes buried in flat-layered anelastic media. The results of the computation, performed for periods greater than 1 second, are presented in two sets of maps of maximum displacement ( d _max), maximum velocity ( v _max) and design ground acceleration (DGA), obtained by using two different criteria in the definition of the input magnitude: (1) values reported in the earthquake catalogue ( M _obs) and (2) values determined from seismotectonic considerations ( M _max). A comparison with the results of a previous probabilistic seismic zoning is made to test the possibility of making intensity — ground motion conversion with the aid of log-linear regressions.
