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Ioannis Papanikolaou - One of the best experts on this subject based on the ideXlab platform.

  • uncertainty in intensity assignment and attenuation relationships how Seismic Hazard maps can benefit from the implementation of the environmental Seismic intensity scale esi 2007
    Quaternary International, 2011
    Co-Authors: Ioannis Papanikolaou
    Abstract:

    Fault slip-rates are of decisive importance for Seismic Hazard Assessment. However, sensitivity analysis in geological fault slip-rate Seismic Hazard maps demonstrates that the uncertainty in the attenuation relationships is much higher than the implied uncertainty in slip-rates, so that even if more accurate slip-rate estimation is achieved, it would have little impact on the final outcomes. This paper quantifies these outcomes using as a test site the area of the Southern Apennines and shows that this uncertainty that is inherent within the traditional intensity scales cannot be reduced. In the area of the southern Apennines, the uncertainty extracted from the expected intensity and the attenuation relationships can modify the final results and the estimated recurrence intervals by as low as 10–25% and as high as 1000%, out-pacing the 20% error of the fault slip-rates. Moreover, in such cases the Hazard pattern follows an irregular spatial distribution and cannot be extrapolated uniformly to the entire map. On the other hand, the recent introduction of the Environmental Seismic Intensity scale (ESI) 2007, due to its quantitative nature, promises to offer higher objectivity in the process of assessing macroSeismic intensities particularly in the epicentral area than do traditional intensity scales that are influenced by human parameters. The ESI 2007 scale follows the same criteria-environmental effects for all events and can compare not only events from different settings, but also contemporary and future earthquakes with historical events, offers higher spatial resolution and coverage and incorporates also site effects. As a result, a re-appraisal of historical and recent earthquakes so as to constrain the ESI 2007 scale may prove beneficial for the Seismic Hazard Assessment by reducing the uncertainty implied in the attenuation laws and eventually in the Seismic Hazard maps. As more data from recent and historical events are gathered, the compilation of an ESI 2007 intensity attenuation relationship should be one of the future goals for Seismic Hazard Assessment.

  • advances and limitations of the environmental Seismic intensity scale esi 2007 regarding near field and far field effects from recent earthquakes in greece implications for the Seismic Hazard Assessment
    Geological Society London Special Publications, 2009
    Co-Authors: Ioannis Papanikolaou, D I Papanikolaou, E Lekkas
    Abstract:

    The new Environmental Seismic Intensity scale (ESI 2007), introduced by INQUA, incorporates the advances and achievements of palaeoseismology and earthquake geology and evaluates earthquake size and epicentre solely from the earthquake environmental effects (EEE). This scale is tested and compared with traditional existing scales for the 1981 Alkyonides earthquake sequence in the Corinth Gulf (Ms ¼ 6.7, Ms ¼ 6.4, Ms ¼ 6.3), the 1993 Pyrgos event (Ms ¼ 5.5) and the 2006 Kythira event (Mw ¼ 6.7). These earthquakes were of different magni- tudes, focal mechanisms and focal depths and produced well-documented environmental effects. The ESI 2007 intensity values and the isoseismal pattern for the 1993 Pyrgos and the 2006 Kythira events are similar to those resulting from the traditional scales, demonstrating that for moderate intensity levels (VII and VIII) the ESI 2007 and the traditional scales comply well. In contrast, the 1981 Alkyonides earthquake sequence shows that there is an inconsistency between the ESI 2007 and the traditional scales both in the epicentral area, where higher ESI 2007 intensity values have been assigned, and for the far-field effects. The ESI 2007 scale offers higher objectivity in the process of assessing macroSeismic intensities, particularly in the epicentral area, than traditional intensity scales that are influenced by human parameters. The ESI 2007 scale follows the same criteria-environmental effects for all events and can compare not only events from different settings, but also contemporary and future earthquakes with histori- cal events. A reappraisal of historical earthquakes so as to constrain the ESI 2007 scale may prove beneficial for Seismic Hazard Assessment by reducing the uncertainty implied in the attenuation laws, which constitute one of the most important Seismic Hazard parameters.

E Lekkas - One of the best experts on this subject based on the ideXlab platform.

  • advances and limitations of the environmental Seismic intensity scale esi 2007 regarding near field and far field effects from recent earthquakes in greece implications for the Seismic Hazard Assessment
    Geological Society London Special Publications, 2009
    Co-Authors: Ioannis Papanikolaou, D I Papanikolaou, E Lekkas
    Abstract:

    The new Environmental Seismic Intensity scale (ESI 2007), introduced by INQUA, incorporates the advances and achievements of palaeoseismology and earthquake geology and evaluates earthquake size and epicentre solely from the earthquake environmental effects (EEE). This scale is tested and compared with traditional existing scales for the 1981 Alkyonides earthquake sequence in the Corinth Gulf (Ms ¼ 6.7, Ms ¼ 6.4, Ms ¼ 6.3), the 1993 Pyrgos event (Ms ¼ 5.5) and the 2006 Kythira event (Mw ¼ 6.7). These earthquakes were of different magni- tudes, focal mechanisms and focal depths and produced well-documented environmental effects. The ESI 2007 intensity values and the isoseismal pattern for the 1993 Pyrgos and the 2006 Kythira events are similar to those resulting from the traditional scales, demonstrating that for moderate intensity levels (VII and VIII) the ESI 2007 and the traditional scales comply well. In contrast, the 1981 Alkyonides earthquake sequence shows that there is an inconsistency between the ESI 2007 and the traditional scales both in the epicentral area, where higher ESI 2007 intensity values have been assigned, and for the far-field effects. The ESI 2007 scale offers higher objectivity in the process of assessing macroSeismic intensities, particularly in the epicentral area, than traditional intensity scales that are influenced by human parameters. The ESI 2007 scale follows the same criteria-environmental effects for all events and can compare not only events from different settings, but also contemporary and future earthquakes with histori- cal events. A reappraisal of historical earthquakes so as to constrain the ESI 2007 scale may prove beneficial for Seismic Hazard Assessment by reducing the uncertainty implied in the attenuation laws, which constitute one of the most important Seismic Hazard parameters.

Dino Bindi - One of the best experts on this subject based on the ideXlab platform.

  • the probabilistic Seismic Hazard Assessment of germany version 2016 considering the range of epistemic uncertainties and aleatory variability
    Bulletin of Earthquake Engineering, 2018
    Co-Authors: Gottfried Grunthal, Fabrice Cotton, Dietrich Stromeyer, Christian Bosse, Dino Bindi
    Abstract:

    The basic Seismic load parameters for the upcoming national design regulation for DIN EN 1998-1/NA result from the reAssessment of the Seismic Hazard supported by the German Institution for Civil Engineering (DIBt). This 2016 version of the national Seismic Hazard Assessment for Germany is based on a comprehensive involvement of all accessible uncertainties in models and parameters and includes the provision of a rational framework for integrating ranges of epistemic uncertainties and aleatory variabilities in a comprehensive and transparent way. The developed Seismic Hazard model incorporates significant improvements over previous versions. It is based on updated and extended databases, it includes robust methods to evolve sets of models representing epistemic uncertainties, and a selection of the latest generation of ground motion prediction equations. The new earthquake model is presented here, which consists of a logic tree with 4040 end branches and essential innovations employed for a realistic approach. The output specifications were designed according to the user oriented needs as suggested by two review teams supervising the entire project. Seismic load parameters, for rock conditions of $$v_{S30}$$  = 800 m/s, are calculated for three Hazard levels (10, 5 and 2% probability of occurrence or exceedance within 50 years) and delivered in the form of uniform Hazard spectra, within the spectral period range 0.02–3 s, and Seismic Hazard maps for peak ground acceleration, spectral response accelerations and for macroSeismic intensities. Results are supplied as the mean, the median and the 84th percentile. A broad analysis of resulting uncertainties of calculated Seismic load parameters is included. The stability of the Hazard maps with respect to previous versions and the cross-border comparison is emphasized.

  • total probability theorem versus shakeability a comparison between two Seismic Hazard approaches used in central asia
    Seismological Research Letters, 2015
    Co-Authors: Dino Bindi, Stefano Parolai
    Abstract:

    The comparison of Seismic‐Hazard maps produced in different countries, or computed for the same country but at different times, is often hampered by the difficulties encountered in properly accounting for the differences among the implemented methodologies. An example of such difficulty is given by the comparison between the Hazard maps computed during the Cold War period for the former Soviet Union, which includes vast regions exposed to high Seismic Hazard (e.g., the central Asian countries and the Caucasus region), and recent Assessments carried out for the same regions following approaches developed in Western countries (e.g., Ullah et al. , 2015). These comparisons should take into account the differences in the underlying methodologies used in the former Soviet Union and, in several cases, still in use. In the Western countries, the process of formalizing the Seismic‐Hazard Assessment within a probabilistic framework (probabilistic Seismic‐Hazard Assessment [PSHA]) was developed during the 1960s at the Universidad Nacional Autonoma de Mexico (UNAM) and at the Massachusetts Institute of Technology (MIT) (Rosenblueth, 1964; Esteva, 1967, 1968, 1970; Cornell, 1968). With the works of Cornell (1971) and Merz and Cornell (1973), PSHA was finally formalized within the context of the total probability theorem, which accounted for ground‐motion variability, and its use then became widespread through the implementation and dissemination of the EQRISK software (McGuire, 1976). A comprehensive review of the early development of PSHA can be found in Bommer and Abrahamson (2006) and in McGuire (2008). On the other hand, the development of a probabilistic framework for Seismic‐Hazard Assessment in the former Soviet Union (hereinafter referred to as the USSR [Union of Soviet Socialist Republics]) was initiated in the 1940s with the works of Medvedev (1947) and developed by Riznichenko in the 1960s (e.g., Riznichenko, 1965, 1992). To quantitatively represent the …

  • probabilistic Seismic Hazard Assessment for central asia
    Annals of Geophysics, 2015
    Co-Authors: Shahid Ullah, Laurentiu Danciu, Anatoly Ischuk, Kanat Abdrakhmatov, Marco Pilz, E. Zuccolo, Dino Bindi, Graeme Weatherill, Natalia Mikhailova, Stefano Parolai
    Abstract:

    Central Asia is one of the Seismically most active regions in the world. Its complex Seismicity due to the collision of the Eurasian and Indian plates has resulted in some of the world’s largest intra-plate events over history. The region is dominated by reverse faulting over strike slip and normal faulting events. The GSHAP project (1999), aiming at a Hazard Assessment on a global scale, indicated that the region of Central Asia is characterized by peak ground accelerations for 10% probability of exceedance in 50 years as high as 9 m/s 2 . In this study, carried out within the framework of the EMCA project (Earthquake Model Central Asia), the area source model and different kernel approaches are used for a probabilistic Seismic Hazard Assessment (PSHA) for Central Asia. The Seismic Hazard is assessed considering shallow (depth < 50 km) Seismicity only and employs an updated (with respect to previous projects) earthquake catalog for the region. The Seismic Hazard is calculated in terms of macroSeismic intensity (MSK-64), intended to be used for the Seismic risk maps of the region. The Hazard maps, shown in terms of 10% probability of exceedance in 50 years, are derived by using the OpenQuake software [Pagani et al. 2014], which is an open source software tool developed by the GEM (Global Earthquake Model) foundation. The maximum Hazard observed in the region reaches an intensity of around 8 in southern Tien Shan for 475 years mean return period. The maximum Hazard estimated for some of the cities in the region, Bishkek, Dushanbe, Tashkent and Almaty, is between 7 and 8 (7-8), 8.0, 7.0 and 8.0 macroSeismic Intensity, respectively, for 475 years mean return period, using different approaches. The results of different methods for assessing the level of Seismic Hazard are compared and their underlying methodologies are discussed.

  • probabilistic Seismic Hazard Assessment of bishkek kyrgyzstan considering empirically estimated site effects
    Annals of Geophysics, 2015
    Co-Authors: Shahid Ullah, Marco Pilz, Dino Bindi, Stefano Parolai
    Abstract:

    It is well known that variability in the surface geology potentially leads to the modification of earthquake-induced ground motion over short distances. Although this effect is of major importance when Seismic Hazard is assessed at the urban level, it is very often not appropriately accounted for. In this paper, we present a first attempt at taking into account the influence of the shallow geological structure on the Seismic Hazard Assessment for Bishkek, Kyrgyzstan, using a proxy (Vs30) that has been estimated from in situ Seismic noise array analyses, and considering response spectral ratios calculated by analyzing a series of earthquake recordings of a temporary Seismic network. To highlight the spatial variability of the observed ground motion, the obtained results are compared with those estimated assuming a homogeneous Vs30 value over the whole urban area. The Seismic Hazard is evaluated in terms of peak ground acceleration (PGA) and spectral acceleration (SA) at different periods (frequencies). The presented results consider the values obtained for a 10% probability of exceedance in 50 years. The largest SA estimated considering a rock site classification of the area (0.43 g) is observed for a period of 0.1 s (10 Hz), while the maximum PGA reaches 0.21 g. When site effects are included through the Vs30 proxy in the Seismic Hazard calculation, the largest SA, 0.67 g, is obtained for a period of 0.3 s (about 3.3 Hz). In terms of PGA, in this case the largest estimated value reaches 0.31 g in the northern part of the town. When the variability of ground motion is accounted for through response spectrum ratios, the largest SA reaches a value as high as 1.39 g at a period of 0.5 s. In general, considering site effects in the Seismic Hazard Assessment of Bishkek leads to an increase of Seismic Hazard in the north of the city, which is thus identified as the most Hazardous part within the study area and which is more far away from the faults.

  • probabilistic Seismic Hazard Assessment for central asia
    Annals of Geophysics, 2015
    Co-Authors: Shahid Ullah, Laurentiu Danciu, Anatoly Ischuk, Kanat Abdrakhmatov, Marco Pilz, E. Zuccolo, Dino Bindi, Graeme Weatherill, Natalia Mikhailova, Stefano Parolai
    Abstract:

    Central Asia is one of the Seismically most active regions in the world. Its complex Seismicity due to the collision of the Eurasian and Indian plates has resulted in some of the world’s largest intra-plate events over history. The region is dominated by reverse faulting over strike slip and normal faulting events. The GSHAP project (1999), aiming at a Hazard Assessment on a global scale, indicated that the region of Central Asia is characterized by peak ground accelerations for 10% probability of exceedance in 50 years as high as 9 m/s 2 . In this study, carried out within the framework of the EMCA project (Earthquake Model Central Asia), the area source model and different kernel approaches are used for a probabilistic Seismic Hazard Assessment (PSHA) for Central Asia. The Seismic Hazard is assessed considering shallow (depth < 50 km) Seismicity only and employs an updated (with respect to previous projects) earthquake catalog for the region. The Seismic Hazard is calculated in terms of macroSeismic intensity (MSK-64), intended to be used for the Seismic risk maps of the region. The Hazard maps, shown in terms of 10% probability of exceedance in 50 years, are derived by using the OpenQuake software [Pagani et al. 2014], which is an open source software tool developed by the GEM (Global Earthquake Model) foundation. The maximum Hazard observed in the region reaches an intensity of around 8 in southern Tien Shan for 475 years mean return period. The maximum Hazard estimated for some of the cities in the region, Bishkek, Dushanbe, Tashkent and Almaty, is between 7 and 8 (7-8), 8.0, 7.0 and 8.0 macroSeismic Intensity, respectively, for 475 years mean return period, using different approaches. The results of different methods for assessing the level of Seismic Hazard are compared and their underlying methodologies are discussed.

Stefano Parolai - One of the best experts on this subject based on the ideXlab platform.

  • total probability theorem versus shakeability a comparison between two Seismic Hazard approaches used in central asia
    Seismological Research Letters, 2015
    Co-Authors: Dino Bindi, Stefano Parolai
    Abstract:

    The comparison of Seismic‐Hazard maps produced in different countries, or computed for the same country but at different times, is often hampered by the difficulties encountered in properly accounting for the differences among the implemented methodologies. An example of such difficulty is given by the comparison between the Hazard maps computed during the Cold War period for the former Soviet Union, which includes vast regions exposed to high Seismic Hazard (e.g., the central Asian countries and the Caucasus region), and recent Assessments carried out for the same regions following approaches developed in Western countries (e.g., Ullah et al. , 2015). These comparisons should take into account the differences in the underlying methodologies used in the former Soviet Union and, in several cases, still in use. In the Western countries, the process of formalizing the Seismic‐Hazard Assessment within a probabilistic framework (probabilistic Seismic‐Hazard Assessment [PSHA]) was developed during the 1960s at the Universidad Nacional Autonoma de Mexico (UNAM) and at the Massachusetts Institute of Technology (MIT) (Rosenblueth, 1964; Esteva, 1967, 1968, 1970; Cornell, 1968). With the works of Cornell (1971) and Merz and Cornell (1973), PSHA was finally formalized within the context of the total probability theorem, which accounted for ground‐motion variability, and its use then became widespread through the implementation and dissemination of the EQRISK software (McGuire, 1976). A comprehensive review of the early development of PSHA can be found in Bommer and Abrahamson (2006) and in McGuire (2008). On the other hand, the development of a probabilistic framework for Seismic‐Hazard Assessment in the former Soviet Union (hereinafter referred to as the USSR [Union of Soviet Socialist Republics]) was initiated in the 1940s with the works of Medvedev (1947) and developed by Riznichenko in the 1960s (e.g., Riznichenko, 1965, 1992). To quantitatively represent the …

  • probabilistic Seismic Hazard Assessment for central asia
    Annals of Geophysics, 2015
    Co-Authors: Shahid Ullah, Laurentiu Danciu, Anatoly Ischuk, Kanat Abdrakhmatov, Marco Pilz, E. Zuccolo, Dino Bindi, Graeme Weatherill, Natalia Mikhailova, Stefano Parolai
    Abstract:

    Central Asia is one of the Seismically most active regions in the world. Its complex Seismicity due to the collision of the Eurasian and Indian plates has resulted in some of the world’s largest intra-plate events over history. The region is dominated by reverse faulting over strike slip and normal faulting events. The GSHAP project (1999), aiming at a Hazard Assessment on a global scale, indicated that the region of Central Asia is characterized by peak ground accelerations for 10% probability of exceedance in 50 years as high as 9 m/s 2 . In this study, carried out within the framework of the EMCA project (Earthquake Model Central Asia), the area source model and different kernel approaches are used for a probabilistic Seismic Hazard Assessment (PSHA) for Central Asia. The Seismic Hazard is assessed considering shallow (depth < 50 km) Seismicity only and employs an updated (with respect to previous projects) earthquake catalog for the region. The Seismic Hazard is calculated in terms of macroSeismic intensity (MSK-64), intended to be used for the Seismic risk maps of the region. The Hazard maps, shown in terms of 10% probability of exceedance in 50 years, are derived by using the OpenQuake software [Pagani et al. 2014], which is an open source software tool developed by the GEM (Global Earthquake Model) foundation. The maximum Hazard observed in the region reaches an intensity of around 8 in southern Tien Shan for 475 years mean return period. The maximum Hazard estimated for some of the cities in the region, Bishkek, Dushanbe, Tashkent and Almaty, is between 7 and 8 (7-8), 8.0, 7.0 and 8.0 macroSeismic Intensity, respectively, for 475 years mean return period, using different approaches. The results of different methods for assessing the level of Seismic Hazard are compared and their underlying methodologies are discussed.

  • probabilistic Seismic Hazard Assessment of bishkek kyrgyzstan considering empirically estimated site effects
    Annals of Geophysics, 2015
    Co-Authors: Shahid Ullah, Marco Pilz, Dino Bindi, Stefano Parolai
    Abstract:

    It is well known that variability in the surface geology potentially leads to the modification of earthquake-induced ground motion over short distances. Although this effect is of major importance when Seismic Hazard is assessed at the urban level, it is very often not appropriately accounted for. In this paper, we present a first attempt at taking into account the influence of the shallow geological structure on the Seismic Hazard Assessment for Bishkek, Kyrgyzstan, using a proxy (Vs30) that has been estimated from in situ Seismic noise array analyses, and considering response spectral ratios calculated by analyzing a series of earthquake recordings of a temporary Seismic network. To highlight the spatial variability of the observed ground motion, the obtained results are compared with those estimated assuming a homogeneous Vs30 value over the whole urban area. The Seismic Hazard is evaluated in terms of peak ground acceleration (PGA) and spectral acceleration (SA) at different periods (frequencies). The presented results consider the values obtained for a 10% probability of exceedance in 50 years. The largest SA estimated considering a rock site classification of the area (0.43 g) is observed for a period of 0.1 s (10 Hz), while the maximum PGA reaches 0.21 g. When site effects are included through the Vs30 proxy in the Seismic Hazard calculation, the largest SA, 0.67 g, is obtained for a period of 0.3 s (about 3.3 Hz). In terms of PGA, in this case the largest estimated value reaches 0.31 g in the northern part of the town. When the variability of ground motion is accounted for through response spectrum ratios, the largest SA reaches a value as high as 1.39 g at a period of 0.5 s. In general, considering site effects in the Seismic Hazard Assessment of Bishkek leads to an increase of Seismic Hazard in the north of the city, which is thus identified as the most Hazardous part within the study area and which is more far away from the faults.

  • probabilistic Seismic Hazard Assessment for central asia
    Annals of Geophysics, 2015
    Co-Authors: Shahid Ullah, Laurentiu Danciu, Anatoly Ischuk, Kanat Abdrakhmatov, Marco Pilz, E. Zuccolo, Dino Bindi, Graeme Weatherill, Natalia Mikhailova, Stefano Parolai
    Abstract:

    Central Asia is one of the Seismically most active regions in the world. Its complex Seismicity due to the collision of the Eurasian and Indian plates has resulted in some of the world’s largest intra-plate events over history. The region is dominated by reverse faulting over strike slip and normal faulting events. The GSHAP project (1999), aiming at a Hazard Assessment on a global scale, indicated that the region of Central Asia is characterized by peak ground accelerations for 10% probability of exceedance in 50 years as high as 9 m/s 2 . In this study, carried out within the framework of the EMCA project (Earthquake Model Central Asia), the area source model and different kernel approaches are used for a probabilistic Seismic Hazard Assessment (PSHA) for Central Asia. The Seismic Hazard is assessed considering shallow (depth < 50 km) Seismicity only and employs an updated (with respect to previous projects) earthquake catalog for the region. The Seismic Hazard is calculated in terms of macroSeismic intensity (MSK-64), intended to be used for the Seismic risk maps of the region. The Hazard maps, shown in terms of 10% probability of exceedance in 50 years, are derived by using the OpenQuake software [Pagani et al. 2014], which is an open source software tool developed by the GEM (Global Earthquake Model) foundation. The maximum Hazard observed in the region reaches an intensity of around 8 in southern Tien Shan for 475 years mean return period. The maximum Hazard estimated for some of the cities in the region, Bishkek, Dushanbe, Tashkent and Almaty, is between 7 and 8 (7-8), 8.0, 7.0 and 8.0 macroSeismic Intensity, respectively, for 475 years mean return period, using different approaches. The results of different methods for assessing the level of Seismic Hazard are compared and their underlying methodologies are discussed.

  • Seismic Hazard Assessment in central asia outcomes from a site approach
    Soil Dynamics and Earthquake Engineering, 2012
    Co-Authors: Dino Bindi, Anatoly Ischuk, Kanat Abdrakhmatov, Stefano Parolai, Natalia Mikhailova, Marco Mucciarelli, Gottfried Grunthal, Joachim Zschau
    Abstract:

    Abstract In the process of updating existing PSHA maps in Central Asia, a first step is the evaluation of the Seismic Hazard in terms of macroSeismic intensity by applying a data driven method. Following the Site Approach to Seismic Hazard Assessment (SASHA) [11] , the evaluation of the probability of exceedance of any given intensity value over a fixed exposure time, is mainly based on the Seismic histories available at different locations without requiring any a-priori assumption about Seismic zonation. The effects of earthquakes not included in the Seismic history can be accounted by propagating the epicentral information through a Intensity Prediction Equation developed for the analyzed area. In order to comply with existing building codes in the region that use macroSeismic intensity instead of PGA, we evaluated the Seismic Hazard at 2911 localities using a macroSeismic catalog composed by 5322 intensity data points relevant to 75 earthquakes in the magnitude range 4.6–8.3. The results show that for most of the investigated area the intensity having a probability of at least 10% to be exceeded in 50 years is VIII. The intensity rises to IX for some area struck by strong earthquakes in the past, like the Chou-Kemin-Chilik fault zone in northern Tien-Shan, between Kyrgyzstan and Kazakhstan, or in Gissar range between Tajikistan and Uzbekistan. These values are about one intensity unit less than those evaluated in the Global Seismic Hazard Assessment Program (GSHAP; Ulomov, The GSHAP Region 7 working group [29] ). Moreover, Hazard curves have been extracted for the main towns of Central Asia and the results compared with the estimates previously obtained. A good agreement has been found for Bishkek (Kyrgyzstan) and Dushanbe (Tajikistan), while a lower probability of occurrence of I=VIII has been obtained for Tashkent (Uzbekistan) and a larger one for I=IX in Almaty (Kazakhstan).

G F Panza - One of the best experts on this subject based on the ideXlab platform.

  • Seismic Hazard maps based on neo deterministic Seismic Hazard Assessment for china Seismic experimental site and adjacent areas
    Engineering Geology, 2021
    Co-Authors: Yan Zhang, Antonella Peresan, Vladimir Kossobokov, Franco Vaccari, Fabio Romanelli, Changsheng Jiang, Shanghua Gao, G F Panza
    Abstract:

    Abstract Many devastating earthquakes inflicted heavy casualties and property losses in the Seismically active China Seismic Experimental Site area (CSES: 97.5° ~ 105.5°E, 21° ~ 32°N). We performed a first-order Seismic zoning based on Neo-deterministic Seismic Hazard Assessment (NDSHA) in the study area delimited by 94° ~ 108°E and 19° ~ 35°N, containing the South-East margin of the Tibetan Plateau and the Sichuan-Yunnan region. The Seismic Hazard is expressed by maps of peak ground displacement (PGD), peak ground velocity (PGV) and design ground acceleration (DGA) values, extracted from synthetic seismograms computed at a regional scale and mapped on a regular grid of 0.2° × 0.2° over the study area. For the computation of synthetic seismograms, we considered and updated all the available geophysical-geological-tectonic information, including historical and instrumental earthquake catalogues, seismogenic zones, seismogenic nodes, focal mechanisms, and geophysical structural models. We tested the performance of our Assessments with available data (i.e., after the Great Wenchuan (2008, May 12th, Ms = 8.0) and Lushan (2013, April 20th, Ms = 7.0) earthquakes) and verified the negligible influence of large events located “far” from the study area. The results indicate the high Seismic Hazard of the region, with a particular attention (i.e., where DGA > 0.6 g) to the areas located around the main fault zones, e.g., the Longmenshan, Anninghe and Zemuhe Fault Zones. These first-order NDSHA zoning findings may serve as a knowledge basis to support both large- to mid-range preparedness actions and (multi-scenario) site-specific studies.

  • neo deterministic Seismic Hazard Assessment and earthquake occurrence rate
    Engineering Geology, 2017
    Co-Authors: Andrea Magrin, Antonella Peresan, Tania Kronrod, Franco Vaccari, G F Panza
    Abstract:

    Abstract The aim of this study is to associate the expected ground motions from Neo-Deterministic Seismic Hazard Assessment (NDSHA) to robust estimates of their long-term average occurrence rates. NDSHA means scenario-based methods for Seismic Hazard analysis, where realistic and duly validated synthetic time series, accounting for source, propagation, and site effects, are used to construct ground motion scenarios. NDSHA, in its standard form, defines the Hazard as the envelope ground shaking at the site, namely the maximum estimate computed from a large set of possible scenario earthquakes. Thus, the standard NDSHA maps provide rather robust and conservative Hazard estimates, which do not require any assumption about the probabilistic model of earthquakes occurrence. Some specific applications, however, may benefit from temporal information about the computed ground shaking, including a gross estimate of its average recurrence time. For this purpose, the definition of the Frequency-Magnitude (FM) relation for earthquakes in the Italian region is performed according to the multi-scale Seismicity model and an occurrence rate estimate is associated to each of the modeled sources. The introduction of occurrence rate estimates in NDSHA also allows for the generation of ground shaking maps for specified time intervals (often improperly referred as “return periods”) that permit a straightforward comparison between the NDSHA and the PSHA maps.

  • update and sensitivity analysis of the neo deterministic Seismic Hazard Assessment for egypt
    Engineering Geology, 2017
    Co-Authors: Hany M Hassan, G F Panza, Fabio Romanelli, Mohamed N Elgabry, Andrea Magrin
    Abstract:

    Abstract The main goal of this work is to provide an update on the Seismic Hazard maps available for Egypt that incorporates the results of recent studies, i.e. revised historical earthquake catalogs, morphostructural zonation data (MZ), revised focal mechanism solutions and mechanical models of the lithospheric structure. This is done within the framework of the neo-deterministic Seismic Hazard Assessment (NDSHA) procedure that may effectively accommodate any reliable new information to adequately compute the earthquake ground motion maps (i.e. PGA, PGV and PGD). Furthermore, with the set of relevant scenario earthquakes, this work provides a large dataset of synthetic seismograms, particularly important for the areas that suffer from the endemic lack of useful strong motion time histories such as Egypt, setting the base toward detailed and comprehensive Seismic microzonation studies. NDSHA aims to supply an envelope value, in other words a value that should not be exceeded, therefore it is immediately falsifiable and verifiable. A sensitivity analysis based on the different ground motion maps, computed adopting different (a) models for the earthquake source process, (b) mechanical models of the crust and (c) mapmaker's preconceptions (e.g. different seismotectonic models), is provided. The maps of difference and ratio between various ground motion maps computed for different variants are shown and discussed in order to explore the influence of using various input models. The results provide the potential users with an adequate spectrum of choices and reliably assess and clearly communicate the possible uncertainties. The availability of a wide spectrum of Hazard maps is a prerequisite to supply valuable information for the significant improvement of a Seismic code.

  • The SISMA prototype system: integrating Geophysical Modeling and Earth Observation for time-dependent Seismic Hazard Assessment
    Natural Hazards, 2013
    Co-Authors: G F Panza, Antonella Peresan, Andrea Magrin, F. Vaccari, R. Sabadini, B. Crippa, A. M. Marotta, R. Splendore, R. Barzaghi, A. Borghi
    Abstract:

    An innovative approach to Seismic Hazard Assessment is illustrated that, based on the available knowledge of the physical properties of the Earth structure and of Seismic sources, on geodetic observations, as well as on the geophysical forward modeling, allows for a time-dependent definition of the Seismic input. According to the proposed approach, a fully formalized system integrating Earth Observation data and new advanced methods in seismological and geophysical data analysis is currently under development in the framework of the Pilot Project SISMA, funded by the Italian Space Agency. The synergic use of geodetic Earth Observation data (EO) and Geophysical Forward Modeling deformation maps at the national scale complements the space- and time-dependent information provided by real-time monitoring of Seismic flow (performed by means of the earthquake prediction algorithms CN and M8S) and permits the identification and routine updating of alerted areas. At the local spatial scale (tens of km) of the seismogenic nodes identified by pattern-recognition analysis, both GNSS (Global Navigation Satellite System) and SAR (Synthetic Aperture Radar) techniques, coupled with expressly developed models for interSeismic phase, allow us to retrieve the deformation style and stress evolution within the seismogenic areas. The displacement fields obtained from EO data provide the input for the geophysical modeling, which eventually permits to indicate whether a specific fault is in a “critical state.” The scenarios of expected ground motion (shakemaps) associated with the alerted areas are then defined by means of full waveforms modeling, based on the possibility to compute synthetic seismograms by the modal summation technique (neo-deterministic Hazard Assessment). In this way, a set of deterministic scenarios of ground motion, which refer to the time interval when a strong event is likely to occur within the alerted area, can be defined both at national and at local scale. The considered integrated approach opens new routes in understanding the dynamics of fault zones as well as in modeling the expected ground motion. The SISMA system, in fact, provides tools for establishing warning criteria based on deterministic and rigorous forward geophysical models and hence allows for a well-controlled real-time prospective testing and validation of the proposed methodology over the Italian territory. The proposed approach complements the traditional probabilistic approach for Seismic Hazard estimates, since it supplies routinely updated information useful in assigning priorities for timely mitigation actions and hence it is particularly relevant to Civil Defense purposes.

  • earthquake recurrence and Seismic Hazard Assessment a comparative analysis over the italian territory
    WIT Transactions on the Built Environment, 2013
    Co-Authors: Antonella Peresan, Andrea Magrin, Anastasia Nekrasova, Vladimir Kossobokov, G F Panza
    Abstract:

    Rigorous and objective testing of Seismic Hazard Assessments against real Seismic activity are a necessary precondition for any responsible Seismic risk Assessment. The reference Hazard maps for the Italian Seismic code, obtained with the classical probabilistic approach (PSHA) and the alternative ground shaking maps based on the neo-deterministic approach (NDSHA) are crosscompared and tested against the real Seismicity for the territory of Italy. NDSHA is a methodology that allows for the sound definition of credible scenario events, based on the realistic physical modelling of ground motion from a wide set of possible earthquakes. The flexibility of NDSHA permits to account for earthquake recurrence and allows for the generation of ground motion maps at specified return periods that permits a straightforward comparison between the NDSHA and the PSHA maps.