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A dynamic analysis of the Makhool dam using Geo-studio software is presented in this paper for the purpose of investigating the seismic behavior of earth dams. With emphasis on the dam's height, soil characteristics, and input motion, this study examines the effect of earthquake excitation on the dam's behavior. With input from the SEEP/W program, the analysis was conducted using the QUAKE/W program. In this study, the horizontal component of motion was taken at three different values: 0.04g, 0.06g, and 0.08g. In addition to total stress in x-direction and y-direction, pore water pressure, and x-displacement, the results were presented in figures. Study findings showed that the horizontal displacement and shear strain of the dam increased with dam height, with the maximum displacement of the dam equal to 94 cm at the end of the earthquake. Besides the type of dam soil, the acceleration of the dam was also affected by the strength of the soil, since weaker soil reduced the acceleration of the dam. The pore-water pressure at the dam's base was the highest, with the horizontal movement increasing with depth. In earthquake zones, seismic evaluation is vital for dam construction, and the research provides valuable advice for designing and building earth dams. [ABSTRACT FROM AUTHOR]

Earthquake is among the most disastrous natural hazards existing in the global economy. Large-scale earthquakes exhibit threats and challenges to the modern society, causing casualties and deaths, impeding socio-economic activities and causing massive economic losses throughout the world. Thus there is a need for an earthquake early warning, detection, and rescue system which can save lives of human, environment, and economy of the world. Tremendous growth in the use of Information and Communications Technology (ICT) applications has opened up new possibilities in characterizing infrastructure, risk area and disaster zones, planning and implementation of seismic hazard reduction measures etc. Furthermore, ICT provides an enormous opportunity for both disaster management systems and earthquake-related authorities (emergency responders, police, public health and seismology departments) to acquire state-of-the-art assistance and improved insights for precise and appropriate decision making. Consequently, it is now of paramount importance to transform from individual monitoring, prediction and decision-making frameworks to smart earthquake management systems which includes decision makers and earthquake affecting people equally with the assistance of recent technological advancements. Even though a significant number of earthquake or seismic hazard papers are published in international journals, there has been no quantitative assessment of information and communication technologies (ICT) in this literature yet encountered. Hence, this study is performed. This paper presents a bi-dimensional scientometric study of research from the perspective of various domains, research areas of seismic hazard and ICT trends over the last 10 years, as indexed in Scopus. The essence behind this study is to unveil the main influencing aspects that govern the publications and its citation structure using scientometric method. The publication pattern is analyzed first, along with related subject categories and contributing countries. Then, citation structure is analyzed which includes the distribution of citations over the years, citing journals, documents, authors and influential institutions along with their impact in terms of citations per paper. Furthermore, the keyword analysis is visualized using VOSviewer. Timeline review of keywords are exported from VOSviewer to pinpoint the hotspots and research trends. This paper provides in-depth understanding of existing seismic hazard research and indicates the emerging ICT trends in this research domain. [ABSTRACT FROM AUTHOR]

This paper presents an analysis of the identification of potential seismic damage in an area called Tanah Patah, Bengkulu City, Indonesia. This study is initiated by conducting site investigation and geophysical measurements. Ground motion prediction is conducted to estimate peak ground acceleration which is then used to estimate the damage intensity level during a large earthquake. A spectral matching method to generate ground motion at investigated sites is conducted. Seismic ground response analysis to observe ground response and soil behaviour is performed. The results show that peak ground acceleration in the study area is about 0.255–0.342 g during a large earthquake. IX is this area's Modified Mercalli Intensity (MMI) level scale. Since sandy soils dominate the study area, several sites could be more vulnerable to undergoing liquefaction. The thickness of potentially liquefiable soils is about 8.6–12.8 m. The results could help local governments develop spatial plans in the study area. [ABSTRACT FROM AUTHOR]

It is reported that earthquakes are accompanied by electromagnetic (EM) anomalies. These anomalies are thought to be caused by earthquakes but their generation mechanism is still unclear. The piezoelectric effect has been proposed as a possible mechanism, particularly in quartz‐rich rocks. However, the EM responses to earthquakes due to such an effect have not been well understood. In this article, we study the EM signals generated by an earthquake source due to the piezoelectric effect. We develop a semi‐analytical method to simulate the EM responses to earthquake sources in a 3‐D layered model and conduct numerical simulations to investigate the characteristics of the EM fields. The results show that the piezoelectric effect in quartz‐rich rocks could be the responsible mechanism for the EM signals recorded during the earthquake. Two kinds of EM signals can be generated by the earthquake, namely, the early EM wave arriving before the seismic waves and the coseismic EM field accompanying the seismic waves. For an Mw 6.1 earthquake, the coseismic electric field is ∼0.1 μV/m and the magnetic field can only reach ∼10−5 nT. We also study the sensitivity of the coseismic EM fields to the rock conductivity. The results indicate that the coseismic EM fields are mainly affected by the conductivity of the shallow layer where the receiver is located, and if the top layer is thin, they are also affected by the conductivity of the deeper layer due to the contribution of the evanescent EM wave created at the interface. Plain Language Summary: When a quartz‐rich rock is under stress, the positive and negative charge centers of quartz crystals are shifted, resulting in a polarization, which manifests macroscopically as the EM radiation. Such a phenomenon is known as the piezoelectric effect. It is a plausible mechanism for the generation of the earthquake‐associated electromagnetic (EM) anomaly. In this paper, we propose a simple method to simulate the EM disturbances generated by an earthquake source arising from the piezoelectric effect. We also conduct numerical simulations to study the properties of the EM fields. The results show that earthquakes can produce two kinds of EM signals. One signal propagates with the speed of the EM wave in the rocks and it arrives earlier than the seismic waves. The other is the coseismic EM field that appears simultaneously with the seismic waves. Such a coseismic signal is restricted to inside of the area disturbed by the seismic wave. Based on the sensitivity analysis, we find that the coseismic EM signal is sensitive not only to the conductivity of shallow rocks, but also to that of the deep rocks. The results also indicate that the electric signals produced by the piezoelectric effect during an earthquake are observable. Key Points: A method is presented to simulate the seismo‐electromagnetic fields due to the piezoelectric effect in quartz‐rich strataAn earthquake source can generate an early electromagnetic (EM) wave and coseismic EM fields due to the piezoelectric effectNumerical results show that the piezoelectric effect is an effective mechanism to produce observable electric signals [ABSTRACT FROM AUTHOR]

This paper reports results of mathematical modeling applied to the stress and strain in epicentral zones before and after the large earthquakes that occurred on June 22, 2002 in the Qazvin Province, northwestern Iran (Mw = 6.4) and the Gujarat, India earthquake of January 26, 2001 (M = 6.9). The modeling relied on a method for calculating stress and strain in a blocky elastic isotropic heterogeneous medium disturbed by a set of faults that are due to an external tectonic stress field. The boundary conditions were specified based on geological and seismological data. It has been shown that the epicenters of large crustal earthquakes occur in zones of high stress concentration at the ends of tectonic faults. Rupture occurs when the relationship between acting tectonic stresses satisfies the requirement σyy/σxx >3, thus connecting zones of high stress. The evolution of the aftershock process is controlled by the stress drop caused by a new rupture, while the resulting aftershock clusters are in spatial correlation with the stress drop zone. The new rupture propagates in the direction of dominant tectonic fault orientation in the region. We show a relationship to exist between rupture length and the possible retrospectively predicted location and magnitude of the earthquake depending on the elastic energy buildup and its possible release under specified structural tectonic conditions. [ABSTRACT FROM AUTHOR]

This paper is the first in a series of studies generalizing the Map of Expected Earthquakes (MEE) medium-term earthquake forecast method and analyzing the prospects for its further improvement. Over the past 35 years, the MEE method has been used in seismically active regions around the world with different tectonic conditions and seismic regimes. The average prognostic efficiency of the algorithm was shown to be 2.5 times higher than for random guessing. The MEE can be further improved and upgraded. The new methods of data processing to be implemented into the upgraded MEE will significantly increase the amount of analyzed data, take into account the specific signs of the seismic process at different depths, use lineament–domain–focal (LDF) models of the structure of seismically active zones as stationary prognostic criteria, and build three-dimensional distributions of the probability of strong earthquakes. The improvement will involve an expansion of the list of used seismological precursors that have a physically justified link with the earthquake preparation process and the development of formalized techniques for identifying these precursors in the prognostic practice. [ABSTRACT FROM AUTHOR]

A destructive earthquake, especially if it occurs in areas of high seismic risk, in the form of certain factors, has a significant impact on the environment, including biodiversity. These factors (earthquake effects) are determined by the strength of the earthquake (manifestations of intensity on the earth's surface), local conditions (geomorphological, geological structure, level of urbanization and seismic risk, etc.), disaster-zone recovery processes (fast and effective recovery, localization and prevention of secondary consequences, environmental protection, state opportunities and political decisions, etc.). It is clear that these three important basic conditions of effects are different in different seismic regions and countries, which means that the impact of an earthquake on the environment is different. To consider the features and factors of the impact of an earthquake on the environment, the 1988 Spitak earthquake—one of the most detailed and comprehensively studied earthquakes in the world—was taken as a test object. The main purpose of this article is to highlight in more detail and more fully the possible natural and human factors of the impact of a strong earthquake on the environment and predict the extent of these impacts. Thirty-six major earthquake factors affecting the environment have been identified, which are conditionally divided into three main groups according to the time of formation and genesis: (a) purely seismic, (b) secondary seismic, and (c) post seismic. The paper also attempts to assess possible changes in these factors depending on global warming and a decrease in precipitation. [ABSTRACT FROM AUTHOR]

This paper presents the results of a detailed study of two relatively strong seismic events, occurred on November, 22, 2016 (МW = 5.0) and April 3, 2017 (МW = 4.8) at the northeastern flank of the Baikal rift zone in the areas of the South Muya and Kalar ranges. Both the events were followed by weak aftershocks (N = 178–539, Кр ≤ 11.0), whose epicenters were densely distributed over an area. The seismic moment tensors and hypocentral depths of the mainshocks were calculated from surface wave amplitude spectra. It has been shown that their sources were formed under the influence of the subhorizontal SE–NW extension and the subhorizontal or inclined NE–SW compression. Both the earthquakes were followed by noticeable macroseismic effects at epicentral distances up to 500 km. In the area of the Baikal−Amur Railway, their shaking intensity was IV–V MSK-64. The results obtained can be used in continuous seismic monitoring at the northeastern flank of the Baikal rift zone and can contribute to an objective seismic hazard assessment of the study area. [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]

Abstract—In this paper, we explore the findings of monitoring the components of the Earth's natural electromagnetic (EM) field obtained in 2020–2021, as well as their link with rather strong seismic events within Baikal Rift Zone (in particular, the Kudarin earthquake (Dec. 9, 2020, Mw = 5.5)). During the observations of the magnetotelluric field more than one month prior to the seismic event, the increased conductivity of the tensor-sensitive parts of the sounded soil was recorded due to the displaced release of conducting fluid to the weak crust zones before the earthquake. 24 hours before the seismic event, the anomalous behavior of the electrical field vertical component (Ez) was observed as U-shaped oscillations every 5-30 s due to the electrical charge excitation and relaxation from the compression of quartz-containing rock. The first approximation showed that the analysis of magnetotelluric (MT) monitoring data could help identify medium- and short-term precursors of seismic events. [ABSTRACT FROM AUTHOR]

The rapid growth over recent decades of the impact of natural disasters on economies, especially in vulnerable areas, urges stakeholders to promote innovative solutions involving risk transfers that account for the new risk exposures. These proposed solutions are designed to optimize and expedite the indemnification process, which can ultimately be beneficial for both policyholders and insurers alike. This article explores the possibility of supplementing the current Romanian dwelling insurance protection scheme with a parametric mechanism. To determine the triggering parameter of the insurance pay-out, the authors consider various hazard scenarios developed based on historical events. This paper focuses on Probable Maximum Loss (PML) determination computed for events with epicenters in the Vrancea (a region and a mountain in the Carpathians) seismic area. This area is the most exposed in Romania to earthquakes, and it includes the capital, Bucharest, which is the urban area with the highest population concentration and, consequently, the highest exposure to the discussed risks. [ABSTRACT FROM AUTHOR]

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Usable/rentable floor areas are crucial for the building owners in reinforced concrete (RC) tall buildings. To address this issue, concrete‐encased (CE) or concrete‐filled (CF) composite columns are proposed as alternative vertical load carrying elements by providing the required strength and ductility, but with smaller dimensions. Comparing the performance of columns with different configurations can be done using moment (M)‐axial load (N) interaction curves. This paper summarizes the approaches proposed by Eurocode 4 and AISC 360‐16 for both types of composite columns, presenting simplified and true curves for a specific class of sections. Two case studies involving hybrid RC tall buildings in Istanbul, which utilized composite columns, are presented along with a comparison with steel‐concrete composite and RC solutions. Numerical results indicate that employing steel‐concrete composite columns resulted in approximately 24% reduction in total cross‐sectional areas for one of the case studies, leading to increased usable/rentable areas. Additionally, concrete‐encased and concrete‐filled composite columns exhibited similar performance in terms of axial load‐moment capacities. The impact of longitudinal rebar ratios is also investigated, revealing that the AISC 360‐16 approach yields smaller bending moments and compression capacities compared to Eurocode 4 due to the significant strength reduction factor considered in calculating the concrete contribution in composite sections. [ABSTRACT FROM AUTHOR]

The paper presents the results of modeling the stress–strain state of the epicentral zone of the strong crustal Hanshin–Awaji earthquake, which occurred in the area of Kobe (Japan) on January 17, 1995, with a magnitude M of 6.9. In this work the author's method for modelling and analyzing the stress–strain state of the epicentral zones of crustal earthquakes was used. The geological, tectonic, and seismological data for the earthquake region are used as input data and boundary conditions for modeling. In this work it is shown that the main rupture arising at the origin of the earthquake is generated in a zone of high stress intensity at a certain ratio of the main tectonic stresses and propagates through areas of anomalously high stress concentration, causing maximum displacements in these zones. The results provide new insights into the focal mechanism of an earthquake, aimed at predicting the location and magnitude of strong crustal earthquakes in earthquake-prone areas. [ABSTRACT FROM AUTHOR]

Investigation of an engineering model for the assessment of the seismic behaviour of large mobile equipment For large mobile equipment in seismically active regions, seismic stability is an essential and often decisive design criterion. The seismic behaviour of such large equipment is usually characterised by complex nonlinear types of behaviour (uplift, tilting and rocking), which are difficult to compute and analyse in practice. In this paper, a highly simplified engineering model is presented or developed step by step, which should be able to represent basic features of the typical behaviour of large mobile equipment transverse to the rail under seismic excitation. The typical rocking motion of the equipment, as determined in previous analyses, is to be reflected in the simplified model. The engineering model will be designed in such a way that it is able to reproduce qualitative statements about uplift and rocking or tilting as a function of incisive model parameters and seismic excitation. The dissipation mechanisms of the model are presented and seismic tilting spectra are generated using different approaches. The suitability and applicability of these approaches for assessing uplift and rocking tendencies for large mobile equipment is reviewed using representative series of bucket wheel machines and stackers as examples. In addition, parameters are determined for quantitative application to further large mobile equipment and the delimitation criteria of qualitative and quantitative applicability are compiled. [ABSTRACT FROM AUTHOR]

This paper presents the results of analysis of the spatial distribution of repeated shocks. Data from the world earthquake catalog of USGS/NEIC from 1973 to 2014 were used. Short time intervals, no more than 10 hours after the main shock, and distances from the epicenter of the main shock, no more than 5°, were considered. The dependence of the number of repeated shocks on the distance from the epicenter was studied. Two properties of the spatial distribution of repeated shocks have been identified. The first property is that the curve describing spatial distribution has its maximum at a certain distance (approximately from 10 to 120 km) from the epicenter of the main shock. The logarithm of this distance is directly proportional to the magnitude of the main shock. The second property is that the position of the maximum does not depend on time, i.e., it is a stable spatial characteristic of the earthquake source. Based on these properties, a new way to determine the size of the rupture zone was proposed. [ABSTRACT FROM AUTHOR]

The objective of this paper is to demonstrate how assessment of seismic vulnerability can be effective in protection against earthquakes. Findings are reported from a case study in a densely populated urban area near an active fault, utilizing practical methods and exact engineering data. Vulnerability factors were determined due to technical considerations, and a field campaign was performed to collect the required data. Multi-criteria decision making was carried out by means of an analytical hierarchy process including a fuzzy standardization. Earthquake scenarios were applied through an implicit vulnerability model. GIS was utilized and the results were analyzed by classifying the state of vulnerability in levels as very low, low, moderate, high, and very high. Seismic resilience was evaluated as vulnerabilities below the moderate state, being about 40% in an intensity of 6 Mercalli and less than 10% in 10 Mercalli. It is concluded that seismic resilience in the area studied is not acceptable, the area is vulnerable in the expected scenarios, and due to the high seismicity of the region, proper crisis management planning is required in parallel with attempts toward retrofitting. In this regard, an emergency map was developed with reference to the assessed vulnerabilities. [ABSTRACT FROM AUTHOR]

Summary: This paper presents a new three‐directional isolator and a new prediction model for base isolation method of buildings to improve the comfort of occupants under subway‐induced environmental vibration. The mechanical properties of the isolator were tested in a laboratory. The results indicated that the stiffness values can satisfy the isolation requirements for environmental vibrations by increasing the thickness of rubber layers, and the sliding bottom is beneficial for protecting the new isolator from instability failures under earthquakes. The suppression effectiveness of the new isolator for three‐directional subway‐induced environmental vibrations was then investigated via field experiments with a full‐scale building. Further, the tri‐axial comfort of occupants inside the building is enhanced significantly. Finally, using the measured data from the field experiments as an input, the new prediction model was proven to be effective for evaluating the vertical vibration levels of the base‐isolated building. As the new prediction model only includes a few of the most influential floor slabs, the modeling workload and computational cost of the prediction analysis are eased. Therefore, the new isolator and the prediction model are beneficial for improving the service performances of the base isolation method, especially for the buildings near subway transportation and in seismic areas. [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]

Two earthquakes of magnitude 6.1mb occurred at the Ahar and around 16000 residential buildings were destroyed. one of the conspicuous issues in the earthquake is property management to reconstruct and confront the crisis. in this regard, since the most damage inflicted on the buildings occurs in the exterior walls, therefore, the most financial resources must be spent on reconstructing this part of damaged buildings. Thus, this paper was conducted in order to reduce expenditure and increase the resistance of the walls. The urban fabric of the area didn’t sustain much damage and only the exterior walls of the buildings were collapsed. Thus, the main aim of this article is to study different types of exterior walls for renewal and reconstruction of buildings in earthquake area. To approach this aim, using group decision-making method. This paper presents the comparison of FUZZY and AHP. in this regard, this research is centralized on types of exterior walls to reconstruct iran earthquake areas (Ahar, Heris, Varzeqan). five main methods have been chosen by asking experts in the related fields and to evaluate and select the best of exterior walls. finally 3D panel wall was selected as the optimal wall for reconstruction of earthquake area. [ABSTRACT FROM AUTHOR]

Türkiye is in a geography where many large and small-scale earthquakes occur due to its location in the earthquake zone. The Kahramanmaraş earthquake on February 6, 2023, and the Hatay earthquake on February 20, 2023, affected individuals with special needs and their families as well as individuals with typical development. This research aims to determine the experiences of experts who meet/support individuals with special needs and their families in the earthquake zone or any province and their recommendations regarding future disasters. Therefore, focus group interviews were conducted with five special education teachers and a psychological counsellor. According to the results of the research, four themes were reached: the needs, the difficulties, the positive aspects of interventions for individuals with special needs after the earthquake and recommendations for a future earthquake. The results obtained from the findings of this study were discussed together with previous studies in the literature and suggestions were made regarding before, during and after disasters. [ABSTRACT FROM AUTHOR]

In the twenty-first century, the seismic design of buildings seems to have become a fully recognised topic. There are guidelines and standards which should be taken into account by designers in seismic areas. Designers using modern international guidelines have ascertained that the behaviour of structures is not as expected. This may be the result of not taking into account the duration of the shock. The duration of surface vibrations could be one of the basic reasons why some buildings collapse or suffer severe damage to bearing systems as a result of long-duration earthquakes despite being properly designed in accordance with current understanding. Another primary reason for such collapse or damage is that some buildings in seismic areas have irregular structural systems that are sensitive to torsional vibrations. In this paper, a five-storey, irregular-shaped RC building model was subjected to different types of excitations: mining tremors, short-duration earthquakes, long-duration earthquakes. The first stage was a modal analysis based on in situ measurement. After model verification using in situ measurements, the building was then subjected to the three forms of excitation. Numerical studies were performed using a verified FEA model of the building in the time domain. The results of the calculations prove that the duration of the intensive phase of extortion is one of the reasons for the lack of building collapse in mining areas. In cases of mining shocks with a short duration of surface vibration, damage to buildings may occur which does not threaten the safety of their construction. Building collapses occur with earthquakes which are characterised by a much longer duration of the intensive phase of excitation compared to mining shocks. The results of in situ observations of RC structures that have survived a history of mining shocks of varied intensities confirm the results of numerical analyses. [ABSTRACT FROM AUTHOR]

Due to the swivel construction, the structural redundancy of cable-stayed bridge is reduced, and its seismic vulnerability is significantly higher than that of non-swirling construction structure and its own state of formation. Therefore, it is particularly important to study the damage changes of each component and stage system during the swivel construction of cable-stayed bridge under different horizontal earthquakes. Based on the construction of Rotary Cable-stayed Bridge in Haxi Street, the calculation formula of damage exceeding probability is established based on reliability theory, and the damage calibration of cable-stayed bridge components is carried out, and the finite element model of cable-stayed bridge rotating structure is established. The vulnerable parts of the main tower and the stay cable components of the cable-stayed bridge are identified and the incremental dynamic analysis is carried out. Finally, the seismic vulnerability curves of the main tower section, the stay cable and the rotating system are established. The results of the study show that the vulnerable areas of the H-shaped bridge towers are the abrupt changes in the main tower section near the upper and lower beams, and the vulnerable diagonal cables are the long cables anchored to the beam ends and the short cables near the main tower. At the same seismic level, the damage exceedance probability of main tower vulnerable section of cable-stayed bridge under transverse earthquake is greater than that under longitudinal earthquake, the damage exceedance probability of vulnerable stay cables under transverse seismic action is less than that under longitudinal seismic action. On the premise of the same damage probability, the required ground motion intensity of the system can be reduced by 0.35g at most compared with the component. Under the same seismic intensity, the system damage probability is 6.60 % higher than the component damage probability at most. The research results have reference significance for the construction of rotating cable-stayed bridges in areas lacking seismic records. [ABSTRACT FROM AUTHOR]

Abstract—: This paper reports the results of numerical modeling of the stress-strain state of the epicentral area before and after the August 24, 2014 earthquake in Napa, California, USA, compared to calculated data obtained in instrumental studies in the dilatation areas based on GPS observation results. Numerical modeling has made it possible to calculate the stress-strain state of the epicentral area affected by the tectonic fault system. GPS observation data on the epicentral area of the earthquake and the results of numerical modeling of the stress-strain state before and after the considered earthquake have been analyzed. A trend toward localization of earthquake epicenters in the region of high stress intensity concentration has been confirmed. It has been proved that aftershock development is due to the drop in stress caused by a new fracture and that the aftershock cluster that occurred was localized in the area of decreased stress intensity. [ABSTRACT FROM AUTHOR]

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Earthquake induced landslides (EIL) represent coseismic effects that heavily affect seismic territories worldwide and must be taken into account in urban planning according to national laws and technical provisions. Inventories of earthquake-triggered landslides and and geotechnical characterization of soils involved into mass movements are commonly prescribed to predict EIL with increasing details as the scale of the study increases. EIL hazard is assessed through several different methods. At urban scale, the deterministic approach of the Newmark's sliding rigid block method is commonly employed to draw EIL hazard maps by calculating permanent displacements triggered by seismic events. Thematic maps built within ArcGis environment have been combined to draw hazard maps through the raster calculator tool (ARCMAPTM 2010). In this paper the Newmark's method is applied to the case study of Deliceto town, located in Daunia Apennine (Apulia, Southern Italy). This territory is characterized by frequent and widespread landslide phenomena triggered by seasonal rainfalls and strong earthquakes, such as the 23rd November 1980 Irpinia earthquake. In particular, Deliceto is affected by the highest seismic level within Daunia territory corresponding to the expected peak ground acceleration (PGA) equal to 0.20 g. The outcomes of the present study suggest that the highest permanent displacements are expected along steep slopes made up of an alternation of limestones and marly clays belonging to the Flysch Faeto Fm. [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]

Most design codes evaluate the non-linear seismic performance of structures using the response reduction/modification factor (R). The value of R is sensitive to a variety of factors in terms of overall ductility and over-strength. In this work, actual R values were assessed for vertical irregularity cases for reinforced concrete bare buildings with moment-resisting frames (MRFs). A significant relationship between R and the vertical irregularity index, calculated from the relative stiffness between adjacent storeys, was derived. Three-dimensional numerical modelling was carried out for soft storey and setback irregularity scenarios using Etabs. Modal pushover analysis was used to obtain the inelastic seismic capacity. It was found that vertically irregular buildings have weak inelastic seismic capacities compared with regular buildings. So, before the design stage, R should be scaled down by 15–40% for single and combined vertical irregularity scenarios. Structures with a combined asymmetric setback with a soft ground storey were found to have the worst R value and R was sensitive to the vertical irregularity index (Vtm) that has R-squared of 80%. So, the vertical irregularity index can be used to specify the allowable vertical irregularity ratio, location and combination of vertical irregularities for each seismic zone. [ABSTRACT FROM AUTHOR]

On 30 September 2009 at 05:16 pm local time (10:16 am UTC), a major earthquake registering a magnitude M 7.6 occurred off the coast of Padang in West Sumatra. This paper presents the observations from a reconnaissance mission that investigated the performance of structures, infrastructure and geotechnical structures within the affected region. As well as presenting the detailed observations made on the mission, insights as to why structures failed and deficiencies in the construction practices of the region are also presented. Considering the high seismic risk of this area and that seismic gaps suggest another earthquake with a magnitude greater than 8.7 may occur, these observations are particularly significant. One of the vital features of this earthquake was a number of very large and devastating landslides that occurred in the district of Pariaman. These landslides were not only extensive, but had an extremely high lethality. Another key feature of the earthquake was the surprisingly high number of government buildings that collapsed. The paper concludes by presenting a number of recommendations for both the rebuilding of failed structures as well as for hazard assessments of existing structures and geotechnical features. [ABSTRACT FROM AUTHOR]

The global objective of sustainable development has been greatly directed toward the preservation of existing structures. Therefore, condition assessment and reconstruction of existing timber structures have been gaining importance in recent times. This is particularly evident on timber roofs whose elements are exposed to degradation, either because of rheological effects or due to the direct influence of moisture and biological factors. In case of accidental events, such as an earthquake, the question of the structure's condition is essential for the condition of the entire building. In order to prove the load-bearing capacity and serviceability of existing structures, as well as to check the need for reconstruction, it is necessary to define crucial parameters that are influencing the condition of materials, elements, and systems. Although there are many non destructive testing methods, the frequency and scope of their use, as well as the decision-making approach, have not been defined. In the paper, non-destructive and semi-destructive methods frequently used for timber structures are explained. A systematic review of criteria to be used in the assessment of load-bearing timber structures in a seismic active area was the main objective of this paper as well as the illustration of non-destructive and semi-destructive test methods through a case study involving roof construction of a hundred-year-old building in Zagreb, Croatia. Pre- and post-earthquake inspection was made. The overall condition of the roof structure after two significant earthquakes can be assessed as satisfactory given that the observed system is a large-span and massive roof structure. The presented results and identification of typical damages after the earthquake are presented in order to facilitate policy makers and for the future implementation of development strategies in the renovation of the city. [ABSTRACT FROM AUTHOR]

This paper describes the application of semi-active variable stiffness damper (SAVSD) for response control of the seismically excited structure. The SAVSD consists of hydraulic damper connected in the form of bracing in a selected story of frame structure. The SAVSD changes its stiffness depending upon the structural response and accordingly adds the control forces in the structural system. In this paper, the comparative study and the performance of SAVSD under different ratios of damper stiffness to structural story stiffness is presented. The specific objective of this study is to evaluate the optimum value of damper stiffness ratio and its importance in structural response reduction. The optimum stiffness ratio is investigated for the structure subjected to four different types of earthquake ground motions. Here, the switching control law and newly proposed modified switching control law are used and the results are compared with uncontrolled and passive control cases. A numerical study is performed on five and ten-story shear building with different configurations of damper placement. The numerically evaluated optimum parametric values are considered for the analysis of the optimum damper placement in the structure. It is revealed that, the proposed modified switching control law is very effective in reducing the story displacements and inter-story drifts without increasing the top floor accelerations. The numerical results of various analyses indicate that SAVSD shows better performance over the passive dampers in reducing the structural responses. [ABSTRACT FROM AUTHOR]

Background: An earthquake with a magnitude of 7.7 occurred in Pazarcık District of Turkey at 04.17 on February 6, 2023 and another earthquake of 7.6 occurred at 13.24 on the same day. This is the second largest earthquake to have occurred in Turkey. The aim of this study is to investigate the earthquake-related level of knowledge, attitudes and behaviours, general health and psychological status of survivors who were affected by the 2023 Kahramanmaraş Earthquake and who were living in Nurdağı District of Gaziantep after the earthquake. Methods: Data of 2317 individuals older than 18 years of age who were living in earthquake neighbourhoods, tents and containers in Nurdağı District of Gaziantep were examined. Variables were evaluated to find out the demographic characteristics and general health status of earthquake victims. General Health Questionnaire (GHQ-12) was used to find out psychological states of earthquake victims. Results: The rate of injuries was 14.2% and leg and foot injuries were the most common with 44.2%. The relationship between injury status; and age, marital status, and being trapped under debris was revealed (p < 0.05). Mean GHQ-12 score of the survivors was 3.81 ± 2.81 and 51.9% experienced psychological distress. In the evaluation with logistic regression, it was found that female gender, being injured in the earthquake, loss of first degree and second degree relatives (with a higher rate in loss of first degree relative), having a severely damaged -to be demolished house and having a completely destroyed house were correlated with higher level of psychological distress (p < 0.05). Conclusion: General characteristics, injury prevalence and affecting factors of earthquake survivors were evaluated in the present study. Psychological distress was found in victims. For this reason, providing protective and assistive services to fight the destructive effects of earthquake is vital. Accordingly, increasing the awareness of people residing in earthquake zones regarding earthquakes is exceptionally important. [ABSTRACT FROM AUTHOR]

Shear-wave velocity of the top 30 m, VS30, is commonly used for prediction of the seismic site response. This paper presents development, validation and uncertainty assessment of a regional VS30model based on a combination of simplified 3D geology and statistically representative velocity values. Results identify soft marine sediments in deep sedimentary basins as zones most susceptible to seismic shaking. Compared to the available urban-scale seismic zonation studies, the regional model showed a success rate of roughly 64% in predicting local site category. The standard deviation was in average 30% of the expected VS30value. [ABSTRACT FROM PUBLISHER]

In this paper, the parameters including maximum regional magnitude ( M), β-value, mean seismicity rate ( λ) and mean recurrence time were calculated for the Zagros belt. The mapping of parameters shows that there are several seismogenic zones in the Zagros with different seismic activity patterns. The results of calculation of the parameters for each seismogenic regions show that the parameters such as β-value, mean activity rate, annual probability and mean return period of events have been decreased from NW Zagros to SE with exception of Qatar-Kazerun transverse fault zone. This pattern is consistent with the increasing convergent rate from 4.5 ± 2 mm/year in the northwestern to 9 ± 2 mm/year in the southeastern part of the Zagros range (Vernant et al. in Geophys J Int 157:381-398, ). The anomalous values of seismic parameters are observed for the two transverse lineaments of the Zagros, Qatar-Kazerun fault zone and Zagros-Makran transition zone. These zones are characterized by high seismicity rate, low β-value and mean return period of earthquakes. The highest value of M coupled with very low seismic activity rate is observed for the MRF. It seems, in this zone, seismic energy is being released by a few relatively large earthquakes with longer return period. The other regions in the Zagros are characterized by high β-value, low seismicity rates and long recurrence time. The differences in the seismicity parameters are due to differing stress regimes and geological or structural heterogeneity of various parts of the Zagros belt . [ABSTRACT FROM AUTHOR]

The seismic performance assessment of earth slopes and systems requires an estimate of the seismically-induced slope displacement (D). Modified Newmark-type analyses are useful to develop an estimate of D. Most simplified seismic slope displacement procedures were developed for shallow crustal earthquakes. In contrast, few procedures are available for subduction tectonic settings, which is especially the case for intraslab earthquakes. This study uses the comprehensive NGA-Sub ground motion database to formulate new seismic slope displacement models for subduction zone interface and intraslab earthquakes using a mixed random variable framework, which allows a straightforward implementation in engineering practice. The models are formulated in terms of the sliding mass properties (its yield coefficient and fundamental period), the spectral acceleration at the degraded period of the slope, and earthquake magnitude with peak ground velocity as an optional parameter. The models reveal that D scales differently for interface and intraslab earthquakes, which is contrary to what has been often assumed. The models also estimate displacement-compatible seismic coefficients for pseudostatic slope stability analyses. This study advances the performance-based seismic design of slope systems affected by subduction zone earthquakes. [ABSTRACT FROM AUTHOR]

Understanding of seismicity and seismotectonics of Delhi and adjoining areas is essential as these areas lie in the seismic zone IV and are geologically confined to the Delhi Fold Belt (DFB), juxtaposed to the Himalayan Frontal Thrust Fold Belt. Owing to the set-up, seismicity in this area is ascribed to the Himalayan Thrust System and activation of DFB Fault Systems. Considerably improved instrumental seismic monitoring in this area and data analysis had resolved three regions of pronounced seismicity that lie close to Sonepat, Rohtak and western part of the NCT Delhi, attributed to activation of various portions of the fault systems of the DFB. Based on seismic telemetry network data, the seismicity pattern analysis revealed that the Mahendragarh Dehradun Sub-Surface Fault (MDSSF) and Delhi Sargodha Ridge (DSR) are the two major zones of structural importance for the nucleation of seismicity in this region. These revelations were corroborated with the fault plane solution of the earthquakes. The dominant mechanism in nucleation of seismicity in DFB is the thrust with minor strike slip. The seismicity and seismotectonics of Delhi and adjoining areas endemic to activation of DFB is reviewed and presented in this paper. [ABSTRACT FROM AUTHOR]

Natural disasters like flood, earthquakes and cyclones are very frequent in India since historical times. As far as the casualties are concerned, globally earthquakes are second in the list after the flood. The loss of property due to these earthquakes is huge and enormous. In the light of the present knowledge base, earthquake prediction is far from being a reality. An early earthquake warning has potential to save the precious human lives. In the present day scenario seismic instrumentation and telecommunication permits the implementation of seismic alert system (SAS) based on the real-time measurement of ground motions near the source. SAS is capable of providing a warning of several seconds before the arrival of destructive seismic waves caused by a large earthquake. SAS is successfully operational in many countries of the world. In a country, like India where earthquakes are taking heavy toll on the human lives and property, seismic alert system may prove to be very important step in natural hazard mitigation strategy. In this paper, an attempt has been made to compute the available alarm time before the destructive earthquake waves reaches to the cities like Delhi, Lucknow, Patna and Kolkata taking Himalaya as the source and feasibility of seismic alert system in Indian scenario. [ABSTRACT FROM AUTHOR]

This paper develops a novel method, based on hidden Markov models, to forecast earthquakes and applies the method to mainshock seismic activity in southern California and western Nevada. The forecasts are of the probability of a mainshock within 1, 5, and 10 days in the entire study region or in specific subregions and are based on the observations available at the forecast time, namely the interevent times and locations of the previous mainshocks and the elapsed time since the most recent one. Hidden Markov models have been applied to many problems, including earthquake classification; this is the first application to earthquake forecasting. [ABSTRACT FROM AUTHOR]

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In this study, Taiyuan loess is used in the analysis of the seismic stability of a loess tunnel. This analysis considers the dynamic parameters of the loess as determined via triaxial compression tests in the literature. In this analysis, the consolidation pressure is converted into the thickness of the overlying loess layer. The spring stiffness and damping coefficients of the viscoelastic boundary are obtained using the maximum dynamic elastic modulus in conjunction with different loess moisture contents and Poisson’s ratios. Additionally, the loess cohesion and internal friction angle are also obtained for different moisture contents. By (1) utilizing the dynamic finite element static shear strength reduction method and the non-convergence rule, (2) taking the safety factor as the assessment standard for loess tunnel stability, and (3) reducing the dynamic parameters of the loess mass until the model calculation is non-convergent, the effects of the moisture content, seismic intensity and loess thickness on the safety factor are obtained. A theoretical basis for the seismic response analysis of this type of loess tunnel is provided by considering the dynamic parameters of loess. [ABSTRACT FROM AUTHOR]

Izmir, the third largest city and one of the major economic centers in Turkey, has more than three million residents and one-half million buildings. The city, located in a seismically active region in western Anatolia, was a subject of the 1997 RADIUS (Risk Assessment Tools for Diagnosis of Urban Areas against Seismic Disaster) project. In this paper, the seismic hazard of Izmir is investigated through probabilistic seismic hazard assessment. First, the seismic setting of Izmir is presented. Considering the statistics of earthquakes that took place in the region during the period 1900-2005, a simple seismic hazard model is used to facilitate the assessment. To account for modeling uncertainties associated with the values of seismicity parameters, a logic tree procedure is employed in carrying out the seismic hazard computations. The resulting weighted average seismic hazard, presented in terms of peak ground acceleration and associated probability of exceedence, could be considered the 'best estimate' of seismic hazard for Izmir. Accordingly, for a return period of 475 years, for rock sites, a PGA value of 0.34 g is calculated. This PGA hazard estimate is close to the current code-recommended design acceleration level for Izmir. [ABSTRACT FROM AUTHOR]

This paper presents the results of research carried out to improve emergency response activities in earthquake-prone areas of Iran. The research concentrated on emergency response operations, emergency medical care, emergency transportation, and evacuation—the most important issues after an earthquake with regard to saving the lives of victims. For each topic, some guidelines and criteria are presented for enhancing emergency response activities, based on evaluations of experience of strong earthquakes that have occurred over the past two decades in Iran, notably Manjil (1990), Bam (2003), Firouz Abad-Kojour (2004), Zarand (2005) and Broujerd (2006). These guidelines and criteria are applicable to other national contexts, especially countries with similar seismic and social conditions as Iran. The results of this study should be incorporated into comprehensive plans to ensure sustainable development or reconstruction of cities as well as to augment the efficiency of emergency response after an earthquake. [ABSTRACT FROM AUTHOR]

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Abstract: In seismic-prone zones with liquefiable deposit piles are routinely used to support structures (buildings/bridges). In this paper, a unified buckling and dynamic approach is taken to characterize this vibration. The pile–soil system is modelled as Euler–Bernoulli beam resting against an elastic support with axial load and a pile head mass with rotary inertia. The emphasis here is to obtain a simple expression that can be used by practicing engineers to obtain the fundamental frequency of the structure–pile–soil system. An approximate method based on an equivalent single-degree-of-freedom model has been proposed. Natural frequencies obtained from the exact analytical method are compared with approximate results. Proposed expressions are general as they are functions of non-dimensional parameters. It is shown that this simplified method captures the essential design features such as: (a) the continuous reduction of the first natural frequency of the structure–pile–soil system due to progressive reduction of soil stiffness due to liquefaction; (b) the reduction in the axial load-carrying capacity of the pile due to instability caused by liquefaction. The results derived in this paper have the potential to be directly applied in practice due to their simple yet general nature. An example problem has been taken to demonstrate the application of the method. [Copyright &y& Elsevier]