Seismic Zone Research Articles

Draft Earthquake Zone Map of India

Draft Earthquake Zone Map of India

Shallow Structure and Seismic Amplification Effects in the Weifang Segment of the Tanlu Fault Zone Based on the Spectral Ratio Method

Abstract The Weifang segment of the Tanlu fault zone (TLFZ) is located in the central section of the TLFZ, eastern China, and has been identified as an earthquake gap zone. Previous studies in the region have mainly focused on the crustal velocity structure and anisotropy, with limited attention to the shallow near-surface structures. In this study, we analyzed the distribution of sediment thickness and evaluated the seismic amplification effects in the Weifang segment of the TLFZ using the horizontal-to-vertical spectral ratio (HVSR) method and the standard spectral ratio (SSR) method. The data we used are from a dense array of 302 three-component seismometers deployed in 2017 for three months. The lowest peak frequency of HVSR indicates that the northwestern part of the study area exhibits relatively thicker sedimentary deposits, estimated to be 800–1200 m in thickness, consistent with both tomographic and geological studies. The SSRs are calculated from 43 regional and teleseismic earthquakes with respect to 12 reference stations. The results from SSR show strong amplification in the 0.2–2 Hz frequency range for sites on the northwestern part, and the amplitude can be up to 15 times larger than that of the bedrock site. We also find significant amplification effects as well as thick sedimentary layers at specific stations along the eastern branch of the TLFZ, suggesting a localized low-velocity zone along the fault. Our results also demonstrate that using the single-site seismic method can provide new constraints on the fine structure and site responses of the fault zone, which are important for seismic hazard assessment.

Reactivation and propagation of the transbrasiliano strike-slip system in Tocantins province, central Brazil: From Ediacaran to Cretaceous

Strike-slip zones are formed by the accommodation and displacement of crustal blocks, reflecting dynamic behavior within the lithosphere. Repeated deformation in these zones can obscure earlier geological processes by creating new structural frameworks and reactivating ancient weakness zones. In central Brazil, the Transbrasiliano Lineament - a major continental-scale strike-slip system - has significantly reworked the Tocantins Province, altering key geological elements that constrain the final stages of Western Gondwana's assembly. Although several seismic events have been linked to this large structure, establishing a direct correlation remains challenging due to its crustal framework being largely obscured by Phanerozoic sedimentary basins. This study presents a multiscale analysis of geological, geomorphological and geophysical data to characterize the Transbrasiliano Lineament dynamic in central Brazil. Our findings reveal a deep crustal discontinuity associated with the Goiás-Tocantins seismic zone, characterized by low-velocity anomalies and a thinner crust within the Brazilian Platform. The complex configuration of this strike-slip system, due to successive reactivations, has displaced and reoriented previous magnetic elements, affecting the Araguaia, Brasília, and Paraguay Belts. Consequently, deformation of the Transbrasiliano Lineament has propagated from the southern Bananal Basin to the northern Paraná Basin, exhibiting a horsetail splay geometry. Structural geophysical analysis indicates that this ongoing reactivation has recorded deformation episodes from the Ediacaran-Cambrian to the Upper Cretaceous.

Epidemiology of respiratory infection pathogens using multiplex RT-qPCR in big earthquakes Area in Turkey (2023)

IntroductionThe Kahramanmaraş earthquake, which has been classified as an earthquake with significant and destructive consequences on a global scale, has been referred to as "the disaster of the century.", occurred on February 6, 2023. A considerable number of structures were destroyed and a significant amount of damage was incurred in 11 provinces, including Kahramanmaraş. Respiratory tract infections are a serious public health problem seen in all age groups among earthquake victims living in tent and container cities. ObjectiveThe aim of the study was to determine the causative agents in respiratory tract samples taken for screening purposes from earthquake victims living in tent cities in the earthquake zone and to provide early diagnosis. MethodGaziantep Provincial Health Directorate Infectious Diseases Unit filiation teams collected nasopharyngeal swabs from earthquake victims living in tent cities around Gaziantep province between March 25 and March 30, 2023. The presence of 18 viruses and 6 bacteria that are causing respiratory tract infections were simultaneously detected by the Real-Time qPCR (RT-qPCR) technique. ResultsIn the present study, respiratory pathogens were detected in 470 (56.62 %) of a total of 830 patients. The most frequently isolated agents were rhinovirus (20 %, 94/470), S. pneumoniae (12.87 %, 60/470), RSV A/B (12.12 %, 57/470), H. influenza type b (10. 85 %, 51/470) and others. Rhinovirus was the most frequently detected pathogen in the study. The coexistence of more than one pathogen was also detected. The most common association was found between HRV and S. pneumoniae (20.93 %, 9/43). ConclusionThe results of the present study indicate that public health measures should be prioritized in natural disasters, and ıt demonstrates that infectious diseases became a significant problem in the time period after the earthquake. Early results can be obtained by screening viral and bacterial pathogen in respiratory tract samples with RT-qPCR, and an early diagnosis is ensured.

Interplay of tectonic and dynamic processes shaping multilayer extensional system in southern-central Apennines

High-hazard seismic zones can remain silent over centuries with meager seismicity rates challenging our understanding of seismic processes. We focus on the comprehensive analysis of cascading episodes of swarms and seismic sequences following the 2009 L’Aquila mainshock (MW 6.3) in the southern-central Apennine that previously experienced ~ M7 earthquakes. We enhance the seismic catalog, unmasking low-magnitude seismicity down to completeness magnitude ML ~ 0, and we unveil that the microseismicity might be secondarily triggered by the L’Aquila mainshock, influencing the frictional properties in the nearby fault zones or opening fault valves generating the intense seismic activity detected from 2009 to 2013. The diffusivity, observed in the most seismic episodes, and the high Vp/Vs values (> 1.88) indicate fluid circulation promoting multilayered extensional seismicity within 11–15 km and 16–23 km depth ranges. Mapping the 3D distribution of seismicity alongside geological data reveals an evident tectonic influence, unveiling unknown geometric aspects and providing the first evidence of a NNE-dipping deformation zone bounding at depths of 11–15 km the overlying fault system. Deeper seismicity suggests a mantellic CO2 ascending shape. These findings enrich the literature on tectonic seismic swarms in extensional domains, providing essential constraints on fluid involvement in the seismic processes and contributing to forthcoming discussions on the seismotectonic setting in high-seismic-risk areas of the Apennines of Italy.

Integrated rehabilitation of reinforced concrete buildings: Combining seismic retrofit by means of low-damage exoskeleton and energy refurbishment using multi-functional prefabricated facade

The European building stock was mostly built before the mid-20th century and is characterized by buildings with high energy demand and high seismic vulnerability. Integrated upgrading interventions are therefore urgently needed for moving towards a more resilient community. In this study, rehabilitation interventions are proposed for reinforced concrete buildings to improve their energy efficiency as well as their structural/seismic performance. An integrated refurbishment aiming at structural, architectural, and energy upgrading is targeted. Energy retrofitting with multifunctional wood-based prefabricated modular facades has been evaluated, as capable of reducing heat consumption by an average of 84 % in different climate zones. More specifically, an exoskeleton system consisting of Prestressed Laminated timber (Pres-Lam) technology is considered, which will act as a structural support-skeleton system for a high-performance “double-skin” solution composed of prefabricated panels. This solution can reduce the seismic risk class in high seismic zones. The seismic-energetic integrated intervention is developed for a representative case study building and evaluated with reference to different climates and seismic zones. Furthermore, a preliminary cost-benefit analysis of the integrated solution has been performed, showing higher benefits when compared to the sole energy retrofit. Specifically, considering the seismic retrofit interventions, the cost analysis pointed out that moving up to higher-use classes results in higher performance and costs. Nevertheless, approximately comparable breakeven times have been obtained in the same seismic region by achieving higher targets. The proposed integrated solution is a promising alternative to demolition and reconstruction, providing a deep energy renovation and structural retrofit, avoiding inevitable waste production, additional energy consumption, and C02 emissions; and allowing for a sustainable renovation of the existing building stock.

Effect of Infilled Frames on Reduction Factor (R) for RC Irregular Structure

Investigating the modification factors as a critical seismic design tool, delineating the anticipated level of inelastic behavior within structural systems during seismic events. Both damping and ductility are included in this factor, particularly at movement nearing maximum capacity. Moreover, it offers valuable insights into buildings' response during earthquakes and the anticipated behavior of structures compliant with building codes during design earthquakes. Essentially, it mirrors the structure's capacity to dissipate energy via an inelastic mechanism. In this research, the infill (RC) structures with various structural irregularities were focused. The selected irregularities included dimension, elevation, and mass. Infill location, number of bays, and seismic zone were the expected R factors for RC frames. Non-linear static pushover analysis was adopted in numerical simulation. The available data gathered from the literature was used to validate the outcomes of the developed models. Additionally, the effects of different types of soil were taken into consideration, and the research results demonstrated that the value of the modification factor (R) for change in stiffness and mass of high-rise buildings for bare and infill (RC) structures is less compared to irregular (RC) structures. It was concluded that the same structure with different types of soil and different parameters has a great effect on the value of R for bare and infill regular and irregular (RC) structures. Furthermore, recommendations for accurate R estimation for RC structures were discussed. Doi: 10.28991/CEJ-2024-010-08-09 Full Text: PDF

Neotectonic structures of the Eastern Taimyr and their relationship with gravitational anomalies and seismicity

The study of the newest structures of the east of the Taimyr Peninsula, expressed in relief, was carried out using the structural and geomorphological method, which allows to identify the latest deformations, which were compared with the features of the gravitational field and its transformants. A good correspondence between gravitational anomalies and the magnitude of erosion uplifts is shown, and the confinement of the selected blocks and their boundaries to the peculiarities of the transformant field is established. The zones of seismicity within the Eastern Taimyr and adjacent territories tend to faults active in the Cenozoic period, as well as to an elongated zone of contrasting values of gravitational anomalies and their transformants of the strike zone.

Probabilistic Seismic Hazard Assessment of the Southwestern Region of Saudi Arabia

In relation to its rapid infrastructure expansion, exemplified by projects like the Najran Valley Dam or the rehabilitation of agricultural terraces, Saudi Arabia stands out among the Arabian Gulf nations. To mitigate the earthquake-related risks effectively, it is imperative to conduct an exhaustive analysis of its natural hazards. The southwesternmost region of Saudi Arabia is the main subject area of this study for the probabilistic seismic hazard assessment (PSHA), which aims to identify the peak ground acceleration (PGA) and spectral acceleration (SA) values. The investigation encompasses a 10% and 5% probability of occurrence over a 50-year exposure time for both B/C and C NEHRP soils. In order to take into account the earthquake activity that takes place in the vicinity of the Red Sea Rift, which in fact may have an impact on the seismic hazard in this active tectonic region, different seismic source zones were especially designed for this evaluation. Various characteristics such as the uncertainties related to the b-value, the expected maximum magnitude, and different ground motion prediction equations (GMPEs) were integrated using a logic tree scheme. Additionally, regression relationships between the computed ground motion values were established, and a novel design response spectrum was developed and recommended for several cities. Regarding the key findings, it is significant to highlight that the seismic hazard decreases towards the northeast, when moving away from the Red Sea Rift, confirming anticipated trends where proximity to the rift corresponds to increased seismic hazard. Notably, cities such as Farasan Island, Jazan, Al Qunfundhah, Al Lith and Al Birk present the highest observed hazard values among all the cities analyzed. For these cities, the obtained maximum SA values for both 475 and 975 years under B/C site conditions are as follows: 0.268 g and 0.412 g, 0.121 g and 0.167 g, 0.099 g and 0.150 g, 0.083 g and 0.135 g, and 0.066 g and 0.118 g, respectively. These results emphasize the crucial necessity of adequately evaluating and thoroughly updating the seismic hazard inherent to these particular areas to enhance the risk reduction and disaster readiness initiatives.

Near-epicenter-based partial matching crossover algorithm for estimating the strong-shaking zone of large earthquakes

Near-epicenter-based partial matching crossover algorithm for estimating the strong-shaking zone of large earthquakes

Assessment of the seismic failure of reinforced concrete structures considering the directional effects of ground motions

Seismic intensity measures at different levels significantly impact the seismic damage of building clusters. Reinforced concrete (RC) structures are a type of building widely used in different regions worldwide. A large amount of field seismic damage observation data indicates that within the same seismic intensity zone, the directional effects of varying ground motions lead to significant differences in damage to RC structures on different floors. However, relatively little research has been conducted on estimating the seismic fragility and vulnerability of RC structures considering the directional effects of seismic action. To further study the directional effect of seismic motion on the damage of different floors, this study conducted dynamic time history and spectral analyses on 1472,379 acceleration records in multiple directions obtained from monitoring at nine actual seismic stations during the 2008 Wenchuan earthquake in China. This paper innovatively reports on the actual damage features of RC structures during the Mw6.2 magnitude Jishishan earthquake in Gansu Province, China, on December 18, 2023 (the most severe destructive earthquake in China in 2023) and analyses the influence of earthquake directionality on the damage to different floors of RC structures. A three-dimensional numerical model of a four-story RC frame structure was established using numerical simulation and the finite element method. Different intensity measures were taken to input seismic excitations of different intensities into the RC structure in the 0°, 30°, 60°, and 90° directions, and damage simulation analysis was conducted. The nonlinear dynamic time history curves of structures under multiple directions of seismic excitation in different intensity zones have been developed. Using the interstory stiffness and interstory displacement angle as engineering demand parameters, damage assessment curves and stress clouds for RC structures with 1–4 floors considering different seismic directional effects were generated. The analysis results and major findings indicate that the seismic sequence in the 0° direction has a relatively heavy impact on the first floor of the RC structure in zone IX, which is consistent with the actual field observation results.

A Critical Evaluation of the Coefficient Method, Capacity Spectrum Method and Modal Pushover Analysis for Irregular Steel Buildings in Seismic Zones

A Critical Evaluation of the Coefficient Method, Capacity Spectrum Method and Modal Pushover Analysis for Irregular Steel Buildings in Seismic Zones

Knowledge and opinions on natural disasters and disaster education of pre-service teachers who survived the 6 February earthquake in Turkey

Human-related events that occur in an unexpected time and affect people’s lives adversely are defined as natural disasters. Today, when we live in the age of technology, several regions are faced with natural disasters such as earthquakes, floods and hurricanes. Not different from various countries in the world, Turkey faces such natural disasters frequently. Especially the earthquake disaster of February 6, 2023, which affected a very broad area, caused many people to suffer. After the earthquake, several problems such as unemployment, need for education and shelter, and psychological traumas, especially among children, emerged. Although preventing natural disasters is not possible, it is a well-known fact that damages can be minimized through disaster education given in schools from an early age. It is of vital importance that Turkey, which is located in an earthquake zone, attaches more importance to disaster education and that students are educated on this subject from an early age, as in countries such as Japan, in order to reduce the disaster damages. Some action has been taken in this area in Turkey especially after the 1999 Marmara earthquake, but the recent major earthquake disaster has shown that more attention should be paid to disaster education. This study was carried out to determine the knowledge and opinions on disaster and disaster education of pre-service teachers who survided the earthquake in Turkey on February 6, 2023. The study group consisted of students studying in different departments of education faculties of universities. The structured interview form developed by the researchers was used as a data collection tool.

The disaster literacy level of society, opinions on disaster management services, and related factors: A case from a province in Turkiye.

This study aimed to investigate individuals' disaster literacy levels, their thoughts on disaster management services, and related factors. The descriptive research was conducted with a total of 480 individuals between the ages of 18 and 60 living in a province in the first-degree earthquake zone in Turkey. The data were collected with the Disaster Literacy Scale and the Disaster Management Services Evaluation Form. In this study, it was found that more than half of the participants had inadequate/moderate disaster literacy. The total disaster literacy score and all subscale scores were found to be higher in individuals who had an earthquake kit at home, had an emergency plan, and had received disaster-related training (p<.05). The majority of the participants found the services provided for disaster management inadequate or very inadequate. In this study, it has been found that a significant portion of the society lacks the desired level of disaster literacy, and the services provided for disasters are deemed insufficient therefore, there is a need for multi-disciplinary national prevention programs to enhance disaster literacy and preparedness in the community, as well as urgently supporting policies to improve disaster-related services. Additionally, due to their comprehensive knowledge of the general structure of society, public health nurses need to play an active role in disaster preparedness and increasing disaster literacy levels.

Evaluating Coseismic Landslide Susceptibility Following the 2022 Luding Earthquake: A Comparative Analysis of Six Displacement Regression Models Integrating Epicentral and Seismogenic Fault Distances within the Permanent-Displacement Framework

Coseismic landslides have the potential to cause catastrophic disasters. Thus, it is of crucial importance to conduct a comprehensive regional assessment of susceptibility to coseismic landslides. This study rigorously interprets 13,759 coseismic landslides triggered by the 2022 Luding earthquake within the seismic zone. Employing the Newmark method, we systematically assess the susceptibility to coseismic landslides through the application of six distinct displacement regression models. The efficacy of these models is validated against the actual landslide inventory using the area under the receiver operating characteristic (ROC) curve. A hazard map of coseismic landslides is generated based on the displacement regression model with the highest degree of fit. The results show that Moxi Town, Detuo Town, the flanks of the Daduhe River, Wandonghe River, Hailuogou River, and Yanzigou River are high-susceptibility areas for coseismic landslides. This study explores factors influencing model fit, revealing that the inclusion of the epicentral distance and the distance to the seismogenic fault in displacement prediction enhances model performance. Nevertheless, in close proximity to fault zones, the distance to the seismogenic fault exerts a more significant influence on the spatial distribution density of coseismic landslides compared to the epicentral distance. Conversely, in regions situated further from fault zones, the epicentral distance has a greater impact on the spatial distribution density of coseismic landslides compared to the distance to the seismogenic fault. These findings contribute to a nuanced understanding of coseismic landslide susceptibility and offer valuable insights for future Newmark method-based coseismic landslide displacement calculations.

Unveiling the heart of disaster nursing: A qualitative study on motivations, challenges, and lessons from the devastating 2023 Turkey earthquakes.

Turkey has faced a notable escalation in earthquake disasters in the last two decades. Despite initiating a health and disaster management system, nurses' pivotal roles and experiences in handling such crises have been disregarded. This qualitative study analyzed nurses' experiences before, during, and after deployment in response to the 2023 Turkey earthquakes to enhance disaster-response efforts. This descriptive qualitative study was conducted between March and May 2023 using semistructured interviews with 15 nurses purposively sampled among those who volunteered to work in the earthquake zone. The MIRACLE and COREQ guidelines were followed for reporting qualitative research. The analysis exposed five main themes for pre-tasking: moral obligation, motivation, insufficient experience, balancing responsibilities, and preparation challenges. The peri-task themes include responsibilities, skills, bravery and characteristics, workload management, teamwork, and outcomes. Post-tasking has three themes: competence assessment, career goals and aspirations, and support. Training and coping with anxiety and stress are common themes for all phases. Disaster relief requires a comprehensive and coordinated response from healthcare organizations, government agencies, and support systems. Providing adequate training, ensuring safety protocols, offering mental health support, and fostering a fair and supportive work environment are crucial steps in mitigating the adverse effects on nurses and, by extension, the patient care process in earthquake-affected areas. Nurse training in disaster preparedness should cover various response methods and involve multiple disciplines. Managers can help by arranging drills, simulations, online courses, and workshops and promoting partnerships for improved collaboration. Psychological support should be included to address emotional challenges. Regularly updating response policies based on past experiences is crucial for preparedness and efficiency.

Seismicity and Tectonics of the Republic of Kosovo

Abstract Kosovo is distinguished by a particularly high degree of seismic activity as a result of its location in the alpine-Mediterranean seismic area. The thickness of the seismic zone in the Earth’s crust is a crucial element in seismotectonics, as it affects the design of fault systems, relative fault activity, earthquake size and distribution within a fault system, and the long-term accumulation of tectonic deformation. Kosovo’s large depressions and high relief make it challenging geomorphologically. The country of Kosovo is divided into numerous chunks along the fault lines because of the inclinations of these prevalent motions. Normal faults, along which differentiations on the order of 2000 m occurred during the neotectonics period, identify the contacts between these blocks. Understanding Kosovo’s seismotectonic characteristics requires an exact analysis of hypocenter parameters when historical earthquakes that have struck the country are reassessed for magnitude. This study deals with the seismicity and tectonics of the territorial space of the Republic of Kosovo.

Ultimate in-plane shear capacity of 3-panel frameless cold-form steel corrugated walls under axial compression

The Frameless building system, developed by BEHLEN Industries LP, is a structural system that incorporates Cold Form Steel Corrugated Wall (CFSCW) components. These include walls, ceilings, and roofs formed by Frameless panels, along with footings, boundary columns, and an optional convex truss. The system employs simple bolt connections, enabling rapid construction without the need for heavy machinery. It is particularly cost-effective and is often utilized in regions with low seismic activity. In high seismic zones, the structural performance of The Frameless building system under combined compression and lateral loads has not been systematically examined. In this study, four full-scale 3-panel Frameless CFSCWs, were tested under combined axial and shear loads. A generic finite element model was proposed to simulate the force-deformation responses and deformed shapes of the 3-panel Frameless CFSCWs. The numerical simulation results were verified using the experimental results. The verified numerical model was then used in parameter study to examine the ultimate shear capacity of 3-panel Frameless CFSCW of different wall thickness, with the presence of axial compression. The results of the study revealed the ultimate shear capacity of 3-panel Frameless CFSCW is linearly correlated with gauge thickness of the wall panel.

Comparison of Seismic Performance of Buildings with Conventional Slab and Flat Slab in Different Zones of Bangladesh

As usable land is scarce in Bangladesh, the demand for high-rise buildings has risen over the past few decades. Conventionally, reinforced cement concrete (RCC) structures in Bangladesh have been used for residential, educational, institutional &amp; commercial purposes. Bangladesh is located in a relatively earthquake-prone region on the fault plane; it is of utmost importance to assess seismic conditions while constructing a structure. Three types of slabs have been analyzed: conventional RCC slab, flat slab with drop panel, and flat slab with drop panel &amp; shear wall. Typically, a conventional RCC slab contains a beam, column &amp; slab with a large thickness of the beam. To avoid this, a flat slab with a drop panel may be used, but it has some limitations. As it has no lateral support, a flat slab with a shear wall can be replaced to gain more stability. According to BNBC 2006, Bangladesh was divided into three seismic zones. However, according to BNBC 2020, it is revised into four seismic zones. Seismic comparisons of three models in four seismic zones have been conducted. Maximum story displacement, maximum story drift, overturning moment and story shear have been found after analyzing three different types of models located in different seismic zones. The maximum story displacement and maximum story drift for flat slabs are greater than conventional slabs and flat slabs with shear walls. Moreover, the displacement between conventional and flat slabs with shear walls varies a little. Maximum overturning moment and story shear: it appears that for the traditional slab, the value is maximum, the flat slab is minimum, and the flat slab with the shear wall is between those two. The model for flat slab has been found to be more flexible than conventional RCC slab and flat slab with the shear wall.

Parametric Study of Structural Seismic Response: Correlation Between Lateral Load, Displacement, and Stiffness

Indonesia, located near the convergence of major tectonic plates, often experiences significant earthquakes that impact buildings. Many houses damaged by earthquakes are simple structures with red brick masonry. This study analyzes the seismic performance of masonry houses using ETABS software, assuming the houses are in seismic zone 4 and built on soft soil. The analysis focuses on the correlation between lateral loads, displacement, and structural stiffness. The results indicate that the maximum lateral load occurs in the X direction, while the maximum displacement occurs in the Y direction, indicating higher flexibility in the Y direction. Higher structural stiffness reduces displacement but also increases inertia forces. The nonlinear correlation between lateral loads and displacement, as well as the decrease in effective structural stiffness with increasing lateral loads, underscores the importance of balancing stiffness and flexibility in structural design. This study provides valuable insights for earthquake-resistant building design, particularly for masonry houses in earthquake-prone areas of Indonesia. The analysis emphasizes the importance of reinforcing critical areas and ensuring a more uniform distribution of lateral loads to enhance structural resilience to earthquakes. Keywords: ETABS, House, Life Safety, Performance, Seismic