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The Greek National Annex for current Eurocode 8 has adopted the seismic hazard zonation map published in 2003 as part of the modifications to the Greek Seismic Code EAK 2000 (EAK 2003). This map, which followed the catastrophic earthquakes that hit the country between 1978 and 2001, includes three seismic hazard zones with peak ground acceleration (PGA) ranging between 0.16 and 0.36 g. In this paper, following the significant progress that has been made worldwide in the last two decades towards the improvement of the definition of seismic actions and the seismic hazard maps using fully probabilistic models, we make a complete proposal for the Greek National Annex of the ongoing revision of Eurocode 8, which includes a new seismic hazard zonation map for Greece, as well as a novel site categorization scheme and related site amplification factors. To this end, we use the results of the European Seismic Hazard Model, ESHM20, as reported by Danciu et al. (The 2020 update of the European Seismic Hazard Model: Model Overview, 2021) which will be adopted as informative reference for the seismic hazard at European level in the forthcoming revision of Eurocode 8 (CEN/EC8). The herein proposed ground shaking zonation for rock conditions includes five zones with PGA values ranging between 0.13 and 0.37 g. For each zone, two newly proposed ground motion parameters, i.e., Sα,475 and Sβ,475, are provided, which are the two parameters used for anchoring the elastic response spectrum as defined in CEN/EC8, along with all the other necessary parameters for the definition of the elastic response spectrum, including site amplification. The proposal for the new seismic zonation is supported by a preliminary investigation of the impact of its adoption on the seismic design of new structures and on the seismic risk of the current building stock in Greece, to help gain a better insight on how important the differences imposed by the new zonation might be for the end-users and the administration. [ABSTRACT FROM AUTHOR]

Several studies have been carried out to assess the building's seismic vulnerability, to mitigate the seismic risk in urban areas, which is one of the most devastating natural hazards causing considerable economic and human losses. These studies must be incorporated to improve the planning of urban areas to have resistant and resilient cities in case of disasters. The seismic feedback has shown that the build-back-better concept has a direct impact on the city's economic growth. In this paper, the existing buildings' resilience is assessed, in order to highlight the capacity of these last to keep the functionality when an earthquake occurs. This building's resilience has been determined for three types of structures: masonry, reinforced concrete and steel, according to the reconstruction time, the reconstruction cost and the damage state. This last has been assessed from empirical fragility curves developed using the log normal distribution for five structures typologies (Unreinforced masonry; reinforced masonry; RC frame; RC shear walls/Mixed RC frame-RC shear walls and steel structures). A seismic resilience scenario was performed using a geographic information system (GIS) and applied for the Blida city (Algeria) classified as a high seismic zone according to Algerian seismic regulations. According to the results found, the old districts of the Blida city, built mainly during the so-called pre-code period, will not be resilient in case of disaster. The other districts built later in the low-code and high-code periods will have, respectively, medium and good functionality. [ABSTRACT FROM AUTHOR]

Purpose: This paper aims to develop preliminary damage scenarios for unreinforced masonry buildings located in low to moderate seismic hazard areas in Algeria, taking into account the specific site effects. Design/methodology/approach: Three soil types were considered in this analysis according to the definition of the Algerian seismic code (RPA99/2003). Peak ground acceleration values were assigned to each soil type issued from a probabilistic seismic hazard analysis (PSHA). To highlight the effect of soil conditions on the seismic vulnerability analysis of masonry buildings, a site vulnerability increment is carried out, and the macroseismic Risk-UE method has been adopted and applied by developing two main seismic scenarios according to both return periods of the PSHA, 100 and 475 years, respectively. Findings: Based on the preliminary results of rock site condition, it can be outlined that the significant damage obtained for different earthquake scenarios discovered a substantial worldwide seismic risk to the building stock of the study area. Once the site effect is integrated into the analysis, more high values of vulnerability indexes and expected damages are obtained. Moreover, it can be concluded that soft soil (S3) is a little bit more influential than stiff soil (S2) on the final vulnerability index compared to (S1). However, the difference between the soil effect S2 and S3 on the vulnerability index can be neglected. Research limitations/implications: Researchers are encouraged to test the mechanical approaches for more detailed outcomes of a specific building analysis. Practical implications: This research proves to the Algerian decision-makers that due to the site effects and the vulnerability of the masonry buildings, an urgent intervention program is required even for existing buildings located in low to moderate seismic hazard areas. Originality/value: Several seismic vulnerability types of research have been conducted in Algeria for the unreinforced masonry buildings in moderate to high seismic areas in which generally the soil effect is neglected. In this context, this research paper proves that due to the site effects and the vulnerability of the masonry buildings, special attention is required even for existing buildings located in low to moderate seismic hazard areas. With this conclusion, the requirement of taking into account the soli effect in the high seismic areas is even more pronounced and should be conducted. [ABSTRACT FROM AUTHOR]

Kavitha and Raghukanth (Acta Geod Geophys 1-33, 2015) proposed an algorithm to forecast the earthquake energy release for the global seismogenic zones. They concluded that 'the developed model is efficient in forecasting the annual earthquake energy release of most of the seismogenic zone'. However, for several representative case studies their predictions not only are significantly smaller than the observations but also have unreasonable uncertainty. This commentary discusses some of the problems associated with the earthquake data selection for the input of modeling, which may improve the accuracy of the earthquake energy prediction. [ABSTRACT FROM AUTHOR]

This paper for the first time improved a Robust Multi-Output machine learning regression model for seismic hazard zoning of Turkey, Iraq and Iran using constructed 3-D shear-wave velocity (Vs), seismic tomography dataset model for the crust and uppermost mantle beneath the study area. The focus of this paper's opportunity is to develop a scientific framework leveraging machine learning that will ultimately provide the rapid and more complete characterization of earthquake properties. This work can be targeted at improving the seismic hazard zones system ability to detect and associate seismic signals, or at estimating other seismic characteristics (crust acceleration and crust energy) while traditionally, methods cannot monitor the earthquakes system. This work has derived some physical equations for extraction of many variables as inputs for our developed machine learning model based on a reliable understanding of the tomography data to physical variables by preparing huge dataset from different physical conditions of crust. We have extracted the velocity values of the shear waves from the original NETCDF file, which contains the S velocity values for every one km of the depths of the crust for the study area from one km down to the uppermost mantle beneath the Middle East. For the first time, this study calculated new seismic hazard parameter called Peak Crust Acceleration (PCA) for seismic hazard analysis by considering the transmitted initial seismic energy through the Earth's crust layers from hypocenter. All machine learning algorithms in this study wrote in python language using anaconda platform the open-source Individual Edition (Distribution). [ABSTRACT FROM AUTHOR]

This document is a compilation of various research papers and abstracts related to seismic activity and earthquake research in Croatia and Hungary. The papers cover topics such as seismic site amplification, site response analysis, local site effects, lithosphere structure, gravity anomaly models, and seismic performance assessment of buildings. The research provides valuable insights into earthquake risk and mitigation strategies in the region. The document also includes links to additional information and resources for further exploration. [Extracted from the article]

Karachi, a sprawling city spanning over 3500 sq. km, exhibits significant variability in seismic hazard across its expanse. This study employs a deterministic approach for seismic hazard assessment due to the unavailability of a long-term seismic archive required for a probabilistic approach, given the city's relatively young age. Furthermore, a novel methodology is employed in this study, utilizing all known faults within Karachi's seismic vicinity for conducting Deterministic Seismic Hazard Assessment (DSHA). Individual hazards associated with each seismic source are estimated, enabling the determination of the most severe hazard for the development of a seismic zoning map. The resulting DSHA-based seismic hazard assessment categorizes Karachi into four seismic zones, ranging from Zone 2A to Zone 4. This paper concludes that for a vast city like Karachi, relying solely on a single fault source for DSHA does not accurately represent the realistic seismic hazard to the region. [ABSTRACT FROM AUTHOR]

The stability of non-compliant masonry buildings often depends on adequate reinforcement measures, expecting detailed structural assessment and reinforcement using proper techniques. Structural assessment of masonry buildings with poor building practices is a key issue in hilly regions in general that requires prompt attention. This paper addresses the seismic assessment of code-deficient unreinforced masonry (URM) buildings and their strengthened counterparts using a confined masonry (CM) structure, located in a hilly region in seismic zone IV of India. By estimating stress parameters, the seismic behavior of the buildings has been evaluated with the help of SAP2000 software and identified corresponding deficient elements of the structures. Intent of the present research is to explore the scope of improvement in structural safety of URM, taking CM as a better alternative focused to hilly areas. For this analysis linear static and dynamic methods have been used being a usual method for the analysis of seismic effects. Analysis reveals that tensile and shear stresses exceed the permissible limits (IS code- 1905:1989) at all floors in case of URM construction for height 9 m ( G + 3 ) which is within limit as all floors for a building of 15 m ( G + 5 ) in case of CM construction. In this case stresses (tensile and shear) exceed on ground floor only which needs to safe guard as the time of design. A overall, CM structure is found a better alternative for constructing moderate rise building in hilly areas. [ABSTRACT FROM AUTHOR]

Viscous dampers enhance the seismic performance of buildings by increasing the capacity for energy dissipation, or damping. Many placement optimisation algorithms currently exist, though they often do not align with code-based verification procedures nor consider optimising performance at multiple seismic hazard levels, at serviceability and ultimate limits. This paper proposes new damper placement algorithms and compares them against eight existing methods on seismic performance at different hazard levels, design iterations required and total computation effort. The comparison is conducted by means of numerical case studies. All methods are applied to a ten-storey reinforced concrete (RC) moment resisting frame (MRF) building, initially meeting the design requirements of typical buildings in a moderate seismic zone in New Zealand. The result showed that the proposed methods and two existing methods can generate a solution that dominates solutions of other existing methods in at least one aspect (e.g. the objective at a hazard level or running time). [ABSTRACT FROM AUTHOR]

In this paper, we tackle the problem of the intensity attenuation at Ischia, a critical parameter in a high seismic risk area such as this volcanic island. Starting from the new revised catalogue of local earthquakes, we select a dataset of 118 macroseismic observations related to the four main historical events and analyse the characteristics of the intensity attenuation according to both the deterministic and probabilistic approaches, under the assumption of a point seismic source and isotropic decay (circular spreading). In the deterministic analysis, we derive the attenuation law through an empirical model fitting the average values of ΔI (the difference between epicentral intensity I0 and intensities observed at a site IS) versus the epicentral distances by the least-square method. In the probabilistic approach, the distribution of IS conditioned on the epicentre-site distance is given through a binomial-beta model for each class of I0. In the Bayesian framework, the model parameter p is considered as a random variable to which we assign a Beta probability distribution on the basis of our prior belief derived from investigations on the attenuation in Italy. The mode of the binomial distribution is taken as the intensity expected at that site (Iexp). The entire calculation procedure has been implemented in a python plugin for QGIS® software that, given location and I0 (or magnitude) of the earthquake to be simulated, generates a probabilistic seismic scenario according to the deterministic or probabilistic models of attenuation. This tool may be applied in seismic risk analyses at a local scale or in the seismic surveillance to produce real-time intensity shake-maps for this volcanic area. [ABSTRACT FROM AUTHOR]

The Andes, located along South America's western side, is among the world's longest mountain ranges and is one of the most intense seismic activity areas caused by the Pacific Oceanic plate sliding under the South American continent, mainly when the range passes through Peru and Chile, covering an area of 3.37 million km2. The Himalayas mountain range is among the most seismically active regions in the world, mainly when the range passes through Nepal, China, India and Pakistan, due to the collision between the Indian and the Eurasian continental plates, covering an area of 1.09 million km2. Eastern Anatolia mountain range of Turkey covering an area of 0.15 million km2 is also one of the most seismically and tectonically active regions due to the frequent occurrence of earthquakes. These three areas and other few in the vicinity of high seismicity were considered for this paper based on in situ working experience for several dam spillways and large dams with heights up to 335 m. Of these 50% under operation, 25% under construction and 25% under final design stages. The earthquake safety of dams is an important topic in dam engineering and dam safety, and the seismic behavior of dams subjected to severe earthquakes and mainly their consequences downstream must be very well defined providing the adequate seismic factors not only from the engineering point of view but also thinking on damage risks, for a proper application. This paper evaluates the main concept of seismic hazard analysis and the PGA value defined for these dams in the Andean, Himalayas and Eastern Anatolia mountain ranges for the MDE, SEE and OBE earthquakes and their implications for the dynamic and static analysis. [ABSTRACT FROM AUTHOR]

Abstract—The paper presents the results of many years of research on the compilation of a consolidated, refined, unified earthquake catalog for the western sector of the Russian Arctic for the entire instrumental observation period, in particular for the period from 1908 to 2020. The catalog includes data on recent seismicity in areas previously unavailable for detailed seismic monitoring. Based on the results of the study, we were able to more accurately determine the spatial distribution of seismicity in the region and compare the instrumental data with parameters of lineament-domain-focal (LDF) models of the General Seismic Zoning maps (GSZ, from Russian term abbreviated as OSR)—OSR-97 and OSR-2016. In the western sector of the Russian Arctic, the highest seismicity is observed in the continent-ocean transition zone, in the Belyi (Kvitøya) Island, Novaya Zemlya and Severnaya Zemlya archipelagos. The very shelf of the Barents and Kara Seas is characterized by rare and scattered seismicity. The configuration, the maximum possible magnitudes, and the depths of the seismogenic layers in the LDF models of OSR-97 and OSR-2016 maps are not always consistent with the instrumental data and need a correction. The consolidated refined earthquake catalog can be used as a basis for the further research aimed at seismic hazard assessment of the territory, construction of geodynamic models, and study of the stress-strain state of the Earth's crust. [ABSTRACT FROM AUTHOR]

Evaluating the seismic vulnerability of regional group structures is essential for effectively quantifying the seismic resilience and risk analysis of regional cities. To study the degree of damage caused by a typical earthquake to the overall group of buildings in a specific area, this paper takes the field observation data of the Wenchuan earthquake on May 12, 2008, in China as the research background and makes empirical vulnerability statistics and classification on all the inspection data of structural groups in Dujiangyan city. The seismic risk experience database (8621 building samples) based on the overall regional group buildings is developed. Using nonlinear regression, probabilistic risk prediction, and a cumulative damage conditional probability model, the empirical vulnerability matrices of six typical groups of buildings in different seismic intensity zones are established. Considering the effects of seismic design, age, purpose, number of floors, and plane shape features on the seismic resilience and vulnerability of regional group structures, a multifactor vulnerability innovation comparison model based on updating the quantitative scale of vulnerability level is developed. Ultimately, an innovative seismic vulnerability update index domain assessment model is proposed to quantify the damage modes of regional group structures. Zonal fragility prediction models of six typical regional structure groups are established. In the analysis results of the multidimensional empirical vulnerability model, it is found that with the increase in the macroseismic intensity grade, the sample number distribution shows a decreasing trend. Additionally, an essential finding is that the damage of the regional reinforced concrete structure is relatively light, indicating that it has a certain seismic resilience. The empirical vulnerability database is used within the proposed model to obtain a seismic vulnerability index. [ABSTRACT FROM AUTHOR]

The goal of this paper is to update the information of the Automated Information Management System of the EMERCOM of Russia Unified Emergency Prevention and Response System in order to increase the reliability of the results of seismic risk assessment and ensure the safety of the population in earthquake-prone areas of the Russian Federation. The study area is Stavropol krai, where, according to general seismic zoning (GSZ) and detailed seismic zoning (DSZ), possible earthquake source (PES) zones with Мmax = 5.0, 5.5, Мmax = 6, and Мmax = 7 have been identified. The relevance of this study follows from the activation of seismicity in recent years on the considered area according to the registration by the Geophysical Survey of the Russian Academy of Sciences (GS RAS), network of seismic events within a wide range of magnitudes with М ≥ 1. The scientific novelty is due to the fact that, for the first time in the study of a single region, the results of all stages of the study are presented. Estimates of seismic hazard and parameters of the seismic intensity attenuation equation are refined on the basis of the analysis of moderate events with magnitudes in the range of M = 3.3–4.5 from the beginning of the last century to the present; the seismic risk indicators and possible consequences of scenario events for the most hazardous possible source zones are computed. For the first time, we have conducted a joint analysis of all variables. Methods of computer simulation are used to assess the risk indicators, along with the Extremum GIS developed with the participation of the authors of this article. Estimates of possible damage due to scenario earthquakes with M = 6.0 and M = 5.0 for separate large cities of Stavropol krai are obtained. [ABSTRACT FROM AUTHOR]

For the first time, a numerical comparison of the General Seismic Zoning (GSZ) maps with the effect of earthquakes that actually occurred after the publication of the maps was carried out. The area of zones of expected intensity on the GSZ map is compared with the area of isoseists from actual earthquakes. It turned out that the isoseist area is on average by an order less than expected according to the GSZ. This paper describes possible reasons for such an overestimation and proposes ways to improve seismic hazard assessments. [ABSTRACT FROM AUTHOR]

This paper aims at investigating the influence of the direction of wind and seismic ground motion on the structural response of four-legged jacket support substructures for bottom-fixed Offshore Wind Turbines located in areas with non-negligible seismic risk. To do that, a parametric analysis that considers thirteen seismic shaking directions, seven wind directions and four earthquake records is carried out. The results are presented in terms of accelerations, axial forces, bending moments and shear forces in the jacket substructure. The NREL 5 MW wind turbine supported on the jacket designed for the phase I of the OC4 project is considered. The response of the system is simulated using an OpenFAST model that takes into account multi-support seismic input, soil–structure interaction and kinematic interaction. The results show that load combinations with aligned wind and ground motion directions are never the worst-case scenario. On the contrary, the largest accelerations are found when the shaking direction acts along the side-to-side direction, and the most significant internal forces are usually found when the ground motion is aligned with one of the diagonals of the base of the jacket and not aligned with the wind direction. The paper also discusses the specific ranges of the angle of misalignment between wind and seismic shaking directions within which the maximum internal forces are expected to be found. • The effect of wind and seismic shaking directions on jackets for OWTs is investigated. • An OpenFAST model that includes SSI, KI and multi-support input motion is used. • A wide parametric analysis is carried out. • Combinations with aligned wind and ground motion directions are never the worst case. • The most relevant wind and ground motion misalignment angles are provided. [ABSTRACT FROM AUTHOR]

Probabilistic seismic hazard assessment (PSHA), including a site-specific amplification study, is crucial to evaluate site-specific spectra of soil sites to better understand the behavioural patterns of the soils under earthquake excitation. This paper represents the results of the PSHA for Assam state, located in the highest seismic zone of India ever delineated to date. In that sense, the study area is divided into ten areal zones concerning seismicity source modelling to represent the seismo-genesis of the Assam state in detail. The earthquake recurrence parameters of each zone are obtained from Gutenberg–Richter (G–R) recurrence relation with updated homogenized and de-clustered earthquake catalogue from 1735 up to 2021. Earthquakes with magnitude greater than 4 (M > 4) are considered using eight attenuation relationships for continental active shallow crust region, subduction zone and intraplate region. Hazard curves are obtained using a logic tree structure thus minimizing the epistemic uncertainty. The peak ground acceleration (PGA) value obtained at the rock outcrop of the Assam state for 10, 5, 2, and 0.5% probability of exceedance in 50 years with return periods such as 475, 975, 2475, and 9975 years lies between 0.24 and 0.34 g, 0.3 and 0.44 g, 0.42 and 0.59 g, and 0.56 and 0.91 g, respectively. The estimated PGA value at rock outcrop level is comparatively higher than that reported in the codal provisions. Site-specific response spectra at bedrock level (Vs = 1100 m/s) for major cities (Jorhat, Tezpur, Silchar, Dibrugarh, Guwahati, Nagaon) of Assam state have been proposed for different earthquake return periods of 475,2475, and 9975 years. Finally, site amplification study is performed for Guwahati city and surface level 5% damped response spectra with PGA of 0.696 and 0.924 g are obtained for earthquake a return period of 2475 and 9975 years, respectively. [ABSTRACT FROM AUTHOR]

Investigation of the out‐of‐plane behavior of non‐load‐bearing masonry walls in German earthquake zones Due to earthquakes, non‐load‐bearing masonry partition walls have to withstand horizontal loads, herein out‐of‐plane loads are of great importance. The out‐of‐plane behavior of masonry walls is very complex due to the strong non‐linearity. Current design methods do not consider important parameters, and detailed investigations of typical non‐load‐bearing masonry types in Germany do not exist. As part of a research project, extensive analytical, numerical and experimental investigations for load‐bearing masonry walls were carried out and a model was developed to determine the out‐of‐plane capacity, considering significant parameters. The results of these investigations were transferred to non‐load‐bearing walls in a simplified manner. With this, the previous methods in the earthquake standards DIN EN 1998‐1/NA (2020) and DIN 4149 (2005) could be reviewed and adjusted to the current state of the art. Based on the updated seismic hazard map, simplified design methodologies were derived and summarized. The model and the derivation of the simplified design methods are presented and discussed in this paper based on a case study. [ABSTRACT FROM AUTHOR]

Cumulative absolute velocity (CAV) is a ground motion intensity measure that is considered more indicative of structure damage than other intensity measures (e.g., PGA). Nevertheless, most seismic hazard assessments are PGA-based rather than CAV-based. In this paper, the first CAV seismic hazard assessment for Taiwan was presented. According to this CAV seismic hazard assessment, central-western and central-eastern Taiwan is of higher CAV seismic hazards than other areas. At the 475-year return period, the CAV of exceedance in those high seismic hazard areas is around 0.6–0.7 g-sec. [ABSTRACT FROM AUTHOR]

In regions of infrequent but potentially damaging seismicity, modern earthquake inventories may be insufficient to provide inputs to seismic hazard analyses (i.e., fault locations and magnitude–frequency relations). As a result, analysis of paleoseismic evidence, such as coseismic landsliding, is commonly used to help elucidate the seismic record, thereby reducing seismic hazard uncertainty. However, while paleolandslides have been investigated widely, existing inverse-analysis techniques (i.e., to constrain the causative earthquake magnitude and/or ground motions) have several shortcomings, namely, they (i) require the location of the causative earthquake to be known, (ii) provide only a lower-bound estimate of seismic parameters, and (iii) are deterministic in nature. Accordingly, this paper proposes a flexible inversion framework that probabilistically constrains seismic source parameters from regional paleolandslide evidence. The outputs of this framework are (i) a geospatial likelihood surface that constrains the location of fault rupture and (ii) a probability distribution of the rupture magnitude. Simulated paleolandslide studies are performed on modern earthquakes with known parameters. These examples demonstrate the framework's provocative potential as well as important lessons for implementation. The proposed framework has the potential to extract new insights from relic landslide evidence in seismic zones worldwide. [ABSTRACT FROM AUTHOR]

This paper reports results from the estimation of peak ground velocities (PGV) and the assessment of earthquake hazard for several areas in the western Alai Valley based on data relating to hypothetical earthquake-related displacements of bedrock blocks using the PGVEM (PGV estimation method). In addition to dominant transverse (relative to the valley trend) seismic pulses consistent with thrust deformations, we also identified shear deformations along the Alay Valley structures. There is some increase in PGV (and felt intensity) in the area of higher seismicity associated with the Main Pamir en echelon Thrust. Overall, the quantiles Q0.8 and Q0.95 of the resulting PGV estimates are consistent with I = 9.5, which is half an intensity grade above the estimated seismic intensity in the map of general seismic zoning (GSZ) for Kirgizia as of 2018. The results suggest that the PGVEM method has promise for refining GSZ maps based on PGV estimates for older strong events. [ABSTRACT FROM AUTHOR]

Dams are parts of the critical infrastructure of any nation, the failure of which would have a high-risk potential on the people and properties within the dam vicinity. Ghana is one of the most seismically active regions in West Africa and has at least 5 large dams across the region, constructed in strategic locations. The area is characterised by low-to-moderate seismicity, yet historical events suggest that major earthquakes that are potentially damaging have occurred in the study basin. This paper summarises the method used to analyse seismic risk and discusses the seismic hazards of three large dams across the study basin based on the seismicity at the dam sites and their risk due to structural properties and the location of each dam. The peak ground acceleration (PGA) values for the dam sites estimated are within the range of (0.31 g and 0.52 g) for 10,000 years return period. The study shows that one large dam has a high-risk class in the basin. This dam should be inspected and analysed for its seismic safety and people's protection in the downstream paths. [ABSTRACT FROM AUTHOR]

• A novel high-performance structural system for tall building application in high seismic zones. • Detailed equivalent energy design procedure for the newly proposed system has been presented. • The seismic performance of the proposed structural system is demonstrated using the detailed nonlinear time history analysis. In this paper, a novel earthquake resilient reinforced concrete core wall system named the controlled rocking outrigger core wall (CROCW) system is proposed. The CROCW consists of two high-performance seismic force resisting systems along its two principal axes. Along one principal axis is the controlled outriggered rocking wall (CORW), where an outrigger is situated at the roof and controlled rocking at the base. Dampers are incorporated within the outrigger and the rocking base to allow CORW to provide stable energy dissipation during earthquake excitation. Along the other principal axis is the self-centering coupled wall (SCCW). In the SCCW system, the self-centering friction dampers are incorporated within the coupling beams to dissipate the earthquake energy, while the base is designed to rock. The proposed CROCW system can be designed using the novel equivalent energy design procedure (EEDP). Four prototype buildings (two different building heights and two different building sites) were designed using the EEDP presented in this paper. The detailed nonlinear time history analysis was conducted to assess the performance of CROCW system. The results demonstrate that the CROCW system can be efficiently designed using the EEDP procedure to achieve a superior performance and low damage response at multiple levels of earthquake shaking intensities. [ABSTRACT FROM AUTHOR]

Investigation of the out‐of‐plane behavior of non‐load‐bearing masonry walls in German earthquake zones Due to earthquakes, non‐load‐bearing masonry partition walls have to withstand horizontal loads, herein out‐of‐plane loads are of great importance. The out‐of‐plane behavior of masonry walls is very complex due to the strong non‐linearity. Current design methods do not consider important parameters, and detailed investigations of typical non‐load‐bearing masonry types in Germany do not exist. As part of a research project, extensive analytical, numerical and experimental investigations for load‐bearing masonry walls were carried out and a model was developed to determine the out‐of‐plane capacity, considering significant parameters. The results of these investigations were transferred to non‐load‐bearing walls in a simplified manner. With this, the previous methods in the earthquake standards DIN EN 1998‐1/NA (2020) and DIN 4149 (2005) could be reviewed and adjusted to the current state of the art. Based on the updated seismic hazard map, simplified design methodologies were derived and summarized. The model and the derivation of the simplified design methods are presented and discussed in this paper based on a case study. [ABSTRACT FROM AUTHOR]

Design ground motion intensities determine the actions for which structures are checked, in the conventional approach of seismic codes, not to fail the target performances. On the other hand, due to inherent characteristics of probabilistic seismic hazard analysis (PSHA), it is expected that site-specific design intensity based on PSHA is exceeded in the epicentral area of moderate-to-high magnitude earthquakes. In the context of regional seismic loss assessment and of the evolution of seismic codes from the regulator perspective, it is useful to gather insights about the extent of the zone around the earthquake source where code-conforming structures are expected to be systematically exposed to seismic actions larger than those accounted for in design. To assess such areal extent based on empirical evidence is the scope of the study presented in the paper. To this aim, peak ground acceleration ShakeMap data for Italian earthquakes from 2008 to 2020 were compared to the current design intensities in the same areas for which the maps are available. This allowed, first, to develop simple semi-empirical models of the exceedance area versus the magnitude of the earthquakes. Second, it allowed to model the probability that an earthquake of given magnitude causes exceedance of the design intensity via logistic regressions. Coupling the first and second class of models provides an approximation of the expected exceedance (logarithmic) area upon occurrence of an earthquake of given magnitude. Such an area can be of several thousand square kilometers for earthquakes occurring relatively frequently in countries such as Italy. [ABSTRACT FROM AUTHOR]

The performance of a monitoring system for civil buildings and infrastructures or mechanical systems depends mainly on the position of the deployed sensors. At the current state, this arrangement is chosen through optimal sensor placement (OSP) techniques that consider only the initial conditions of the structure. The effects of the potential damage are usually completely neglected during its design. Consequently, this sensor pattern is not guaranteed to remain optimal during the whole lifetime of the structure, especially for complex masonry buildings in high seismic hazard zones. In this paper, a novel approach based on multi‐objective optimization (MO) and genetic algorithms (GAs) is proposed for a damage scenario driven OSP strategy. The aim is to improve the robustness of the sensor configuration for damage detection after a potentially catastrophic event. The performance of this strategy is tested on the case study of the bell tower of the Santa Maria and San Giovenale Cathedral in Fossano (Italy) and compared to other classic OSP strategies and a standard GA approach with a single objective function. [ABSTRACT FROM AUTHOR]

Structural reliability methods are employed in this paper for nationwide probabilistic seismic hazard analysis of Iran and in-depth seismic hazard and hazard sensitivity analysis of Downtown Tehran. The companion paper proposes two analysis approaches based on reliability methods and presents the technical framework for such analyses. The first approach was based on Monte Carlo sampling reliability analysis, which is employed here to conduct hazard analysis at a grid comprising 3695 sites throughout Iran. The results are used to produce nationwide hazard maps for the peak ground acceleration, spectral acceleration, and cumulative absolute velocity. The other analysis approach employs the first- and second-order reliability methods and importance sampling and is applied to the seismic hazard analysis of Downtown Tehran. This analysis identifies the seismic sources that are most influential on the seismicity of Tehran. In addition, reliability sensitivity and importance measures are employed to identify the most influential sources of uncertainty on the seismic hazard at Downtown Tehran. For instance, they identify the geometry of, and the rupture location on, adjacent faults, the shear wave velocity, and the intra-event residuals of ground motion prediction models as the most important sources of uncertainty. [ABSTRACT FROM AUTHOR]

This paper presents a new probabilistic framework for seismic hazard assessment and hazard sensitivity analysis. Hazard in this context means the probability of exceeding a measure of ground shaking intensity, such as peak ground acceleration and spectral acceleration. The main components of the proposed framework include structural reliability methods to estimate exceedance probabilities and their sensitivities, and multiple probabilistic models for earthquake occurrence, magnitude, location, and ground motion. This paper presents two analysis approaches. The first approach utilizes the first- and second-order reliability methods and importance sampling. This approach efficiently yields the hazard exceedance probabilities at a single site. The second approach employs the Monte Carlo sampling reliability method and yields the hazard exceedance probabilities at a multitude of sites in a single analysis, which is suited for large-scale seismic zonation. This paper also presents the probabilistic models that are suited for such analyses with an emphasis on characterization of epistemic uncertainties. Finally, novel sensitivity measures are proposed for hazard sensitivity analysis. These measures provide a framework to identify the most important uncertainties and guide the research to reduce these uncertainties over time. The proposed approach is validated and showcased by an illustrative example. The companion paper presents a comprehensive application to hazard analysis of Iran. [ABSTRACT FROM AUTHOR]

Tunnel portal sections located in the soft-hard rock junction are vulnerable to the strong earthquake motions in seismically active regions. The main objective of this paper is to investigate the seismic response of tunnel portals located in the soft-hard rock junction. Taking the Baiyunding tunnel in northeast China as a background, a shaking table test with a geometric scaling ratio of 1:30 was built. Details of test setup and procedures are introduced first and then the test results are presented. The discussion of the results is based on the peak ground acceleration (PGA), the longitudinal, the contact stress, and the safety factor. The results show that the soft section of the soft-hard rock junction suffers remarkable damages under strong seismic motions, while the hard rock section is less affected by earthquakes. The increasing soft rock range causes a rise of the forced displacement of tunnel linings, which, together with the seismic inertia force, leads to the increase of the contact stress of the linings, and ultimately resulting in the deterioration of the tunnel seismic safety. To mitigate the seismic damage of tunnel portals in the soft-hard rock junction, rock grouting, bolt support, and other effective reinforced methods should be considered in the seismic design of the soft section. [ABSTRACT FROM AUTHOR]

the last decade central Italy was struck by devastating seismic sequences resulting in hundreds of casualties (i.e., 2009-L'Aquila moment magnitude [Mw] = 6.3, and 2016-Amatrice-Visso-Norcia Mw max = 6.5). These seismic events were caused by two NW-SE--striking, SW-dipping, seismogenic normal faults that were modeled based on the available focal mechanisms and the seismic moment computed during the relative mainshocks. The seismogenic faults responsible for the 2009-L'Aquila Mw = 6.3 (Paganica Fault--PF) and 2016-Amatrice-Visso-Norcia Mw max = 6.5 (Monte Vettore Fault--MVF) are right-stepping with a negative overlap (i.e., underlap) located at the surface in the Campotosto area. This latter was affected by seismic swarms with magnitude ranging from 5.0 to 5.5 during the 2009 seismic sequence and then in 2017 (i.e., a few months later than the mainshocks related with the 2016 seismic sequence). In this paper, the seismogenic faults related to the main seismic events that occurred in the Campotosto Seismic Zone (CSZ) were modeled and interpreted as a linkage fault zone between the PF and MVF interacting seismogenic faults. Based on the underlap dimension, the seismogenic potential of the CSZ is in the order of Mw = 6.0, even in the case that all the faults belonging to the zone were activated simultaneously. This has important implications for seismic hazard assessment in an area dominated by the occurrence of a major NW-SE--striking extensional structure, i.e., the Monte Gorzano Fault (MGF). Mainly due to its geomorphologic expression, this fault has been considered as an active and silent structure (therefore representing a seismic gap) able to generate an earthquake of Mw max = 6.5-7.0. However, the geological evidence provided with this study suggests that the MGF is of early (i.e., pre- to syn-thrusting) origin. Therefore, the evaluation of the seismic hazard in the Campotosto area should not be based on the geometrical characteristics of the outcropping MGF. This also generates substantial issues with earthquake geological studies carried out prior to the recent seismic events in central Italy. More in general, the 4-D high-resolution image of a crustal volume hosting an active linkage zone between two large seismogenic structures provides new insights into the behavior of interacting faults in the incipient stages of connection. [ABSTRACT FROM AUTHOR]

Assessing seismic risk in low-to-moderate seismic activity areas like French mainland is a challenge. In these areas, the estimation of large earthquake hazard calls for models driven by sparse observation data and interpretative seismic knowledge. This leads models used in probabilistic seismic hazard assessment (PSHA) and declustering algorithms to large epistemic uncertainties that are overrepresented due to the large amount of parameters used in it. To concentrate epistemic uncertainties into one single method, we intend to limit the number of parameters under consideration by using the non-parametric inter-event time method. This method is empirical and needs a lot of data to be accurate. In the context of sparse large earthquake data, this paper proposes an implementation of the inter-event time method that ensures the stability of main shock proportions for sparse seismic data. We call this implementation magnitude of inferred main shock proportion (MIMP). This method is applied to the historical French seismic catalogue. We use a Monte Carlo Markov Chain to sample the whole space of magnitude uncertainties contained in this catalogue. We produce a set of equiprobable main shock proportion–magnitude and frequency–magnitude distributions. Results are discussed in the light of reference works published in the literature. [ABSTRACT FROM AUTHOR]

Ultra-high voltage converter stations are significant electric power infrastructures with a high electric energy load. To quantitatively evaluate the seismic and recovery capability of a UHV converter station, this paper proposes a multi-model probabilistic resilience assessment framework divided into four analysis modules for hierarchical evaluation. The conditional probability set of the functional state between network nodes is determined using a matrix-based approach. Taking connectivity and power transmission capacity into account, the functional reliability model was built through the improved Bayesian network. A multi-parameter quantification of the post-earthquake recovery process was carried out by constructing the stepped functional recovery function as well as the time-varying seismic resilience function. The economic loss assessment model was built from multiple aspects. Taking a typical ± 800 kV UHV converter station as a case study for seismic resilience analysis, the probabilistic resilience assessment was realized, and variation trends of the multi-parameter expected value were obtained by mathematical expectation. This article shows that taking measures to postpone the sensitive interval of the system helps to avoid the seismic active area. This avoidance of seismic activity is the objective of optimization. The proposed framework can serve as a reference for the operation and optimization of power systems. • A vulnerability analysis method based on the improved Bayesian network was proposed. • A multi-parameter quantified time-varying function of recovery and resilience was established. • A set of multi-model probabilistic resilience assessment framework was built. • An economic loss assessment model considering direct and indirect effects was carried out. [ABSTRACT FROM AUTHOR]

This paper presents results from 21 large-scale experiments on steel columns that examined their collapse behavior as related to steel moment resisting frames (MRFs). The test specimens included wide-flange and square hollow structural shapes (HSS) and were tested until complete loss of their lateral load-carrying capacity. The test results suggest that the collapse rotations of steel columns under collapse protocols, representing near-fault events, are two to three times larger than those of their counterparts under standard symmetric cyclic protocols, regardless of the examined cross-sectional compactness. Conversely, when ground motion duration is an important seismic hazard characteristic, the collapse behavior of steel columns is reasonably traced with a standard symmetric cyclic protocol. It is shown experimentally that steel columns have an inherent reference energy dissipation capacity regardless of the employed loading history. Axial shortening attributable to local buckling is up to 10 times larger in interior than in end columns, which leads to differential axial shortening within a steel MRF story even at modest lateral drift demands during subduction zone seismic events. The test data underscore that the formation of local buckling at a column's fixed end caps the strain demands at about 1% near complete joint penetration welds between the column and the base plate, even when the transient axial load demand becomes tensile. Simpler welds may provide adequate ductility in steel columns featuring cross sections near the compactness limits for highly ductile members according to current design standards. It is shown that the estimated rotations by current ASCE 41 acceptance criteria for collapse prevention are 5–10 times smaller than the measured collapse rotations, even for columns with moderately compact profiles. [ABSTRACT FROM AUTHOR]

Abstract—The paper addresses the problems associated with the maximum earthquakes in a seismically active region. Pisarenko and Rodkin (2009; 2010; 2015) proposed an alternative to the ambiguously determined parameter of the maximum regional magnitude Mmax in the form of a clearly defined and statistically substantiated parameter of the maximum possible magnitude of an earthquake in a given region on a given future time interval T. In this work, we study the statistical characteristics of this parameter—quantiles with a given confidence level q. For the first time, the estimates for the bias, standard deviation, and root mean square deviation of these quantiles are conducted on a large set (1000) of independent samples (synthetic catalogs) with known distribution law. This allowed us to compare the true accuracy of the resulting estimates with that obtained in the case of using one catalog for which the distribution law is not known. The real efficiency of the quantile estimates is assessed from the examples with the exact known quantile values, and stability and robustness of these quantiles as an informative and important characteristic of seismic risk is demonstrated. The conducted comparisons make it possible to estimate the scatter of the quantiles in the region of large times T and with very high confidence levels q. The quantile estimates of the maximum possible events in a future time interval are substantially more robust at a stronger downward bend of the frequency–magnitude graph. A relationship is derived between the quantiles of a single earthquake and the quantiles of a maximum earthquake in the future time interval T. This relationship establishes the equivalence between the length of interval T and the level of significance (reliability) q, which in the case of heavy-tailed distributions should be taken into account in seismic risk assessment. The statistical analysis is carried out using two different methods of parameter estimation: by maximum likelihood estimation and by Bayesian approach. Both methods proved to be approximately equally efficient. Based on these methods, it is concluded that the estimate of the long-term seismic hazard for the regions with a distinctly pronounced downward bend of the frequency–magnitude graph is fairly stable and robust. [ABSTRACT FROM AUTHOR]

Thematic maps, such as seismic risk maps, are a useful tool that researchers use for representing the adverse outcomes that a natural catastrophic event can have over the territory. Generally, in those studies, major attention is focused in urban areas, where the human activities are concentrated. Main concerns are about the existing building stock, mostly composed by structures not compliant with modern seismic design criteria. The realization of a risk map is a complex task that involves the combination of data coming from different field of expertise, such as geology, geotechnical and structural engineering. The paper describes how the application of prospecting and surveying techniques (geological surveys, drilling, down-hole, MASW) allowed a decisive improvement in the geological knowledge of the area, contributing to define the subsoil model for the purposes of seismic microzonation. The interpretation of geophysical and geotechnical data and their correlation with geological units are explained and finally the microzonatic map is presented. The paper also reports the seismic geotechnical characterization executed with laboratory tests including the resonant column and cyclic torsional shear test on undisturbed samples. The results are summarized in terms of variation of stiffness and damping with shear strain. Finally, the use of wireless sensor technology for structural monitoring has significant benefits when the time available for access is often severely limited, by representing an effective way of managing risks once that an area of concern has been identified. The aim of the study is the acquisition of a local knowledge on issues related to seismic risk that may affect urban areas, through the acquisition, management and sharing of complex information. The available information, collected by sensor network, have been combined together in a Geographical Information System tool. The results provide a reliable representation of the seismic risk at urban scale to be used when planning the mitigation measures to be undertaken in order to improve the prevention and reduction of the disastrous effects of the earthquakes. [ABSTRACT FROM AUTHOR]

Fault caused by earthquake is harmful to buried pipelines. Long-distance transportation pipelines will inevitably cross the seismic fault zones. In this paper, a numerical simulation model of X80 pipeline under reverse faulting with a crossing angle of 60° was established. Damage evolution mechanism of buried steel pipeline was analyzed. Effects of internal pressure and diameter-thickness ratio on the stress, strain and displacement of pipeline were discussed. The results show that the buckling phenomenon is more severe in the hanging wall than that in the footwall for reverse fault. For non-pressure pipeline, local collapse occurs on the compression side. When the pipeline wall buckles, the axial stress is released, and high-stress is mainly concentrated on the collapsed position. For pressure pipeline, the internal pressure aggravates the buckling degree. Then, wrinkles appear on the compression side. The results can provide a reference for anti-seismic construction, repair and maintenance of buried pipeline. [ABSTRACT FROM AUTHOR]

While there has been significant research on probabilistic seismic hazard analysis (PSHA) using several different seismic sources, this paper focuses particularly on understanding the spatially varying seismic hazard controlled only by earthquakes. In that vein, regarding Turkish seismicity, this study is the first of its kind to explore this conundrum from a Bayesian point of view and offer new estimates to compare with the existing ones. In this study, a national-extent peak ground acceleration (PGA)–driven hazard map (upon 90% quantile of maxima, VS30 = 760 m/s, and a return period of 475 years) was created and then compared both with the old and new versions of the officially recognized seismic hazard maps of Turkey. Regarding 10 earthquake-prone cities, the new PGA estimates were compared with those picked from these two maps. Next, individual site-based hazard estimates were drawn for these city centers considering the return periods of 43, 72, 140, and 475 years. The present hazard map was in compliance with the seismotectonic setup of Turkey and its PGA estimates were slightly high compared with the last two hazard maps for some specific regions, most of which are located in major active fault zones with a history of intense seismic activity, albeit the figures for low seismic zones were relatively low. With this study, it becomes clear that the process of PSHA, which innately requires a long and tiresome effort, can instantaneously be performed against the changing of catalog data over time, and thence prompt evaluations on variations can consequently be made. [ABSTRACT FROM AUTHOR]

The seismic hazard and risk analysis represents an important research domain and it acts as a connector between the earthquake engineering new advances and the sustainable development of the society. Romania is one the European countries with the highest seismic potential. Within this context, the seismic hazard analysis is an essential component for the seismic hazard mapping, for the seismic risk scenarios design and analysis, for preparing the seismic risk mitigation and reduction strategies, on one hand, and for the development of the post-disaster interventions, as well as the recovery and reconstruction activities, on the other hand. This paper generally presents the natural hazards for Romania and the necessity of studying their effects. Some examples are used to highlight the earthquake effects upon vulnerable structures. The main procedures for seismic risk analysis and the standards provisions for the structural vulnerability assessment along with their advantages and disadvantages are then summarized. [ABSTRACT FROM AUTHOR]

An M 7.4 earthquake occurred near the town of Izmit on August 17, 1999 causing enormous casualties and economic losses: over 15 000 victims and several thousand irreparably damaged buildings and structures. The earthquake produced a set of fractures and fissures in the ground extending for more than 70 km from the Gulf of Izmit, with a new tectonic fault being formed that is more than 150-km long. This paper reports results from mathematical modeling of the state of stress and strain in the epicentral zone before and after the Izmit earthquake along with seismological observations. The modeling used a method for calculating the state of stress and strain in a blocky elastic isotropic heterogeneous medium that has been disturbed by a system of faults caused by an external tectonic stress field, with the boundary conditions being specified from seismological data. We show that the epicenters of large crustal earthquakes tend to occur in areas of highly concentrated stress intensity under a definite relationship between the principal stresses. The aftershock process is due to the release of stresses produced by a new rupture, while the resulting aftershock clusters correlate spatially with the zone of released stress intensity. The tectonic rupture is assumed to propagate toward zones of high stress intensity. The results obtained in this study can be useful in a deterministic approach to the assessment and prediction of earthquake hazard, as well as the length and area of earthquake rupture. [ABSTRACT FROM AUTHOR]

The current seismic prevention strategy is based on a unitary approach aimed at a risk mitigation, also at territorial level. The Italian guidelines for the assessment and mitigation of seismic risk of cultural heritage provides indications for the seismic analysis of protected cultural heritage, with the aim of specifying a path of knowledge, assessing the level of safety and planning possible improvements. The Italian building heritage is very vast and heterogeneous and was devastated by earthquakes due to its high vulnerability; therefore, the seismic risk mitigation also requires the availability of simple and handy analysis tools. The aim of this paper is the illustration of an easy, although approximate, procedure for the evaluation of the seismic safety index and the optimization of strengthening interventions. The procedure is applied to buildings located in the province of Caserta. The analyses are performed with reference to two types of buildings that are particularly recurrent and representative of the building heritage of this area and placed in areas with different seismic hazard. [ABSTRACT FROM AUTHOR]

• The first CLT building in North America adopting self-centering HD was investigated. • An advanced 3D numerical model of the building was developed in OpenSees. • Building with the novel HD showed higher resilience than that with traditional HD. Balloon-framed cross-laminated timber (CLT) construction has a number of advantages when compared to platform-type construction; however, many international standards only include provisions for the latter as there is little research reported on the seismic performance of the former. In this paper, a seismic fragility assessment of a 4-storey balloon-framed CLT building in Vancouver, Canada, is presented. This structure is the first in North America that adopts a self-centering friction-based technology for the hold-downs (HDs). The seismic performance of the building was assessed by performing incremental dynamic analysis (IDA) on a three-dimensional finite element model using Cascadia Subduction Zone ground motions, and compared to a second building model with conventional dowel-type HDs. The analyses at the design intensity level showed that the self-centering building had an average maximum inter-story drift ratio of 0.67%, well below the 2.5% drift limit specified in the National Building Code of Canada. Based on the IDA and taking into account uncertainties, the building had a collapse margin ratio of 2.96 and a 5.2% probability of collapse at the design level. Compared to the conventional HDs, the friction-based HDs did not improve the building's collapse capacity, but reduced the building drift by more than 20% at lower damage states, demonstrating the effectiveness of designing balloon-framed CLT structures with a resilient self-centering HDs in high seismic zones. [ABSTRACT FROM AUTHOR]

Producing accurate seismic hazard map and predicting hazardous areas is necessary for risk mitigation strategies. In this paper, a fuzzy logic inference system is utilized to estimate the earthquake potential and seismic zoning of Zagros Orogenic Belt. In addition to the interpretability, fuzzy predictors can capture both nonlinearity and chaotic behavior of data, where the number of data is limited. In this paper, earthquake pattern in the Zagros has been assessed for the intervals of 10 and 50 years using fuzzy rule-based model. The Molchan statistical procedure has been used to show that our forecasting model is reliable. The earthquake hazard maps for this area reveal some remarkable features that cannot be observed on the conventional maps. Regarding our achievements, some areas in the southern (Bandar Abbas), southwestern (Bandar Kangan) and western (Kermanshah) parts of Iran display high earthquake severity even though they are geographically far apart. [ABSTRACT FROM AUTHOR]

This paper evaluates the effect of local site conditions on the seismic hazard of the relocated new Balakot town as a result of the complete destruction of old Balakot city due to the 2005 Muzaffarabad Earthquake. New Balakot town has been placed in a high seismic zone according to the Building Code of Pakistan because of its vicinity to active seismogenic faults. Representative sites from the new Balakot town have been selected to evaluate the local site effects. The acceleration time series was used as suite input motion in the ground response analysis selected from the worldwide earthquake catalog and matched to the target spectrum of Balakot. The site-specific equivalent linear (EL) and nonlinear (NL) analyses were conducted for which the ground model was developed based on the field and laboratory geotechnical test results. The mean surface ground response spectrum and also the mean Amplification Factor showed that the suite input motions were de-amplified and amplified respectively below and above the fundamental period of the site. The mean maximum amplification factor at 0.4 s shows that a four-story building may be subjected to resonant conditions. The transfer function that relates the amplitude of incident and transmitted motion at interface resulted in different mean peak ground acceleration. The higher surface peak ground acceleration value was obtained from that of suit base motions. The NL analysis was observed to yield more conservative maximum AF and PGA values in comparison to the EL analysis. This study is helpful to provide improved and site-specific values of ground acceleration based on local site effects of the new Balakot town, which is an important locality in the 2005 Muzaffarabad earthquake-affected region. • Balakot is one of the cities that was severely affected during the 2005 earthquake. • The paper evaluates the local site condition for the major distresses and will be helpful to provide improved site-specific values of ground acceleration based on local site effects. • For model development, linear analysis was carried out based on field and laboratory testing. • The impedance ratio of layered soil deposit affects the AF and accelerates time history at 374 layer interface and surface. • Therefore different mean PGA values can be obtained at the interface. A general trend showed that the mean PGA value (0.55 g) of suite input motions was increased to 0.63 g at the surface. [ABSTRACT FROM AUTHOR]

The 2010 Mw = 8.8 Maule earthquake, which occurred in the subduction contact between the Nazca and the South American tectonic plates off the coast of Chile, represents an important opportunity to improve understanding of the distribution and controls for the generation of landslides triggered by large megathrust earthquakes in subduction zones. This paper provides the analysis of the comprehensive landslide inventory for the Maule earthquake between 32.5° S and 38.5° S. In total, 1226 landslides were mapped over a total area of c. 120,500 km2, dominantly disrupted slides. The total landslide volume is c. 10.6 Mm3. The events are unevenly distributed in the study area, the majority of landslides located in the Principal Andean Cordillera and a very constrained region near the coast on the Arauco Peninsula, forming landslide clusters. Statistical analysis of our database suggests that relief and lithology are the main geological factors controlling coseismic landslides, whilst the seismic factor with higher correlation with landslide occurrence is the ratio between peak horizontal and peak vertical ground accelerations. The results and comparison with other seismic events elsewhere suggest that the number of landslides generated by megathrust earthquakes is lower than events triggered by shallow crustal earthquakes by at least one or two orders of magnitude, which is very important to consider in future seismic landslide hazard analysis. [ABSTRACT FROM AUTHOR]

In this study, we use a spatially smoothed seismicity procedure for seismic hazard analysis in North China seismic zone by establishing four spatially smoothed seismicity models according to the seismic catalogs of North China and calculating peak ground acceleration (PGA) values with 10% probability of exceedance in 50 years. The results show considerable differences between seismic hazards based on different models in certain areas, which is attributable to disparities in the seismicity levels of the four seismic models in those areas. In general, seismic hazard based on different models can be used as reference to evaluate uncertainty. In this paper, we also compare the mean PGA based on four spatially smoothed seismicity models with another PGA calculated using the zoning method based on surface seismic sources adopted for generating the Seismic Ground Motion Parameter Zonation Map of China, and find that the results of the two methods are largely similar, both of which can reflect the seismic hazard level of North China. However, there are differences at certain points, which are because the zoning approach adopts the same earthquake occurrence rate in the seismic source, while the spatially smoothed seismicity approach has different occurrence rates at different points. The discrepancies between the two can be attributed to differences in the principles adopted when potential seismic sources are classified. In particular, the PGA values of Beijing with 10% probability of exceedance in 50 years is 177.0cm/s2, 214.2 cm/s2, 252.8 cm/s2, and 187.5 cm/s2 in four spatial seismicity models, respectively. These PGA values are very important for evaluating the uncertainty of seismic hazard in Beijing. This study is an attempt to perform seismic hazard analysis using spatially smoothed seismicity models in China and recommends using this approach for areas where seismic sources are not clearly identified. [ABSTRACT FROM AUTHOR]

The probabilistic nature of seismic ground motion intensity measures such as peak ground acceleration and spectral acceleration ordinates has been extensively studied during the last decades. However, their spatial correlation is mostly considered without any event-to-event variability, using a mean estimate from a number of seismic events. The present study quantitatively evaluates the event-to-event uncertainty of intraevent spatial correlations, using 39 well-recorded earthquakes. Results indicate a high event-to-event variability in the correlation model parameters, which if taken explicitly into account, would improve regional hazard and risk analyses. Event magnitude was found to be a statistically significant predictor variable of the model parameter, however it explains less than 20% of the total event-to-event variability. Moreover, clustering of site conditions, tectonic region, and fault mechanism are not statistically significant as predictor variables of the spatial correlation model parameter. Finally, this paper proposes a simple Monte Carlo approach for considering the high event-to-event variability of spatial correlation models, taking advantage of the Markov dependence of residuals for reducing the number of correlated variables to be simulated. This approach can be used with different intraevent spatial correlation models, as long as proper estimates of the dispersion of their parameters are considered. [ABSTRACT FROM AUTHOR]

Seismic evaluation of existing reinforced concrete buildings that are classified as non-conforming to modern earthquake standards is an urgent priority, since this class of buildings represents the majority of the built environment throughout the world. To address this need a simple procedure for rapid seismic assessment (RSA) of the earthquake demand and available capacity of existing buildings has been devised and calibrated through field applications. RSA is based on first principles, considering the prevalent failure modes of the load bearing components of the structure, and easily accessible information regarding the geometric and material characteristics of the structure. In this paper the RSA method is further improved by introducing expressions for direct estimation of the local drift demands of the examined building at peak seismic response using the structure's unique geometric and material properties. The accuracy of the RSA procedure is evaluated through application and comparison of the assessment results with the recorded seismic responses of two model experimental structures that had been tested under pseudo dynamic loads simulating earthquake effects, reported in the literature. The example structures were chosen because they were full-scale structures with relatively simple layout (planar frames), in order to develop an instructive paradigm of the RSA's application for the interest of practitioners. [ABSTRACT FROM AUTHOR]

Research in the field of anthropogenic seismicity (AS) requires not only seismicity data but also data regarding the progress of the technological/production activities which is the origin of the induced or triggered seismic events. Such data are typically restricted and proprietary, and therefore, usually not available for independent researchers who wish to develop, perform and verify scientific research. The induced seismicity-European plate observing system (IS-EPOS) web portal offers to its user's access to data, applications and documents in order to facilitate AS research. IS-EPOS web portal has been designed to serve as one of the main pillars of the Thematic Core Service—-Anthropogenic Hazards belonging to pan-European multidisciplinary research infrastructure created within the EPOS program. IS-EPOS platform is open for research community and general public according to its rules of access. The platform is operating since January 2016 and is now integrated in the EPOS Integrated Core Services. IS-EPOS e-platform promotes new opportunities to study and comprehend the dynamic and complex solid earth system by integrating the use of multidisciplinary data, data products, analysis models and online applications. The integration of existing and new national and transnational Research Infrastructures increases the access and use of multidisciplinary data recorded by the solid earth observing systems, acquired in laboratory experiments and/or produced by computational simulations. In this paper, we describe the structure and the main innovative characteristics implemented in IS-EPOS. The platform is open to accommodate data integrated within other research projects, and it is continuously being updated with improvements in existing features and implementations of new ones. An appendix at the end of the article provides a summary of acronyms and abbreviations in order to make the reader familiar with the terms used throughout the manuscript. [ABSTRACT FROM AUTHOR]