Earthquake Risk Research Articles

Gravity Modelling Insights into Crustal Structure: Moho Depth and Subsurface Structures in Central Sulawesi

Abstract The present study examines the underlying structures and Moho depth’s geological implications in Central Sulawesi. Comprehending the underlying features of this area is essential for evaluating seismic risks and geological mechanisms. From the World Gravity Map 2012 (WGM 2012), we used a 2D radially-averaged power spectrum analysis of Bouguer gravity anomalies. The Moho depth is around 31 km in the northwest and northeast, with significant fluctuations in the middle and eastern regions. Although the northeastern and northwestern regions have similar depths, the center region has a lower Moho depth. On the other hand, the Palu-Koro Fault limit is marked by the eastern area, which corresponds to the Matano Fault, mirroring the center region. Furthermore, substantial orogenesis inside the Eastern Tokorondo Complex is suggested by Moho depth thinning, especially in the central, eastern, and southern portions. Our research emphasizes Central Sulawesi’s complicated geological structures, marked by variable Moho depth and underlying formations. With implications for earthquake risk assessment and hazard reduction, these insights advance our knowledge of the region’s geological processes.

A Brief Review of Vulnerability, Preparedness and Resilience Measures of Anticipated Istanbul Earthquake

This review examines the seismic vulnerability of Istanbul, a city uniquely positioned at the crossroads of Asia and Europe and exposed to significant earthquake risks due to the North Anatolian Fault (NAF). By synthesizing data on historical seismic events, urban development patterns, and current building and infrastructure resilience, the paper highlights the complexities of disaster management in a densely populated and rapidly growing metropolis. It critically evaluates the effectiveness of existing preparedness and mitigation strategies, including legislative frameworks, urban planning policies, and community-based resilience efforts. The review also identifies gaps in the current approach to earthquake risk reduction and suggests areas for improvement, emphasizing the need for an integrated, multi-sectoral approach to enhance the city's capacity to withstand and recover from future seismic events. The findings underscore the importance of proactive planning and the adoption of innovative technologies in building a resilient Istanbul.

Reevaluating soil amplification using multi-spectral HVSR technique in La Chana Neighborhood, Granada, Spain

This work presents a thorough reevaluation of soil amplification in the La Chana neighborhood of Granada through a pioneering application of the horizontal-to-vertical spectral ratio technique on seismic noise data using various spectral approaches. The research recycles old seismic noise data recorded at 34 stations with 2 Hz instruments in the year 2010, supplemented with additional measurements recorded with broadband seismometers at nearby locations in the years 2013 and 2017. Initial traditional processing identifies a narrowband dominant frequency around 1.5 Hz, attributed to artificial or anthropogenic sources. To address this, the Maximum Entropy Algorithm was implemented to smooth the spectral response below 1 Hz, and filter out frequency peaks with very narrow spectral bands, while preserving the narrowband frequency around 1.5 Hz in some records. The Thomson Multitaper method further refined the spectral ratio, emphasizing the detection and suppression of narrow frequency bands that may be related to industrial activity. The results demonstrated the reappearance of the 1.5 Hz frequency, but this time without narrow bandwidths, indicating its possible correlation with the natural ground movement. Fundamental periods, ranging from 0.45 s to 0.88 s, suggest a diverse lithological composition, indicating the presence of layers of sands, clays, conglomerates, and carbonates over a basement that represents the main impedance contrast in the area. The multispectral approach surpasses conventional methods in precision and reliability, providing valuable insights for earthquake risk assessment, urban planning, and engineering decisions in seismically active regions.

Analysis and Statistical Assessment of Liquefaction Potential Using SPT-N Approach in Bhandara Region Maharashtra: Implications for Infrastructure Development

The Bhandara area in Maharashtra, India, has a lot of earthquakes, so its liquefaction potential needs to be studied in detail to help with building infrastructure. This research uses the Standard Penetration Test (SPT-N) method to check how easily the dirt in the area can become liquefied. When SPT-N numbers are added to soil qualities and seismic factors, they are used to figure out how likely it is that the ground will liquefy when it is loaded with earthquake energy. Different types of dirt and different levels are more or less likely to liquefy, according to the results. The makeup of the soil, the level of the groundwater table, and the history of earthquakes are some of the most important things that affect the liquefaction potential. The study finds places where there is a high risk of liquefaction that are also expected to have big building projects. These results make it clear how important it is to include liquefaction mitigating measures when designing and building roads, houses, and other important infrastructure to make sure it is safe and strong. The study also gives a plan for future earthquake risk ratings in the area, showing how important it is to keep an eye on and update records of soil data and earthquakes. Using the SPT-N method along with current geotechnical and earthquake analysis methods, this study gives a full picture of the area's liquefaction risk. The results have big effects on the growth of infrastructure because they help engineers and managers make smart choices about how to lower risks, improve design, and make infrastructure in the Bhandara region last longer and be safer. In the larger field of geotechnical engineering and crisis preparation, this study adds to it by showing how important specific studies are for building strong infrastructure in areas that are prone to earthquakes.

Recent Holocene activity and regional tectonic significance of the northern segment of the red river fault zone

The Red River Fault Zone is a large-scale right-lateral strike-slip fault zone with relatively strong activity during the Quaternary Period. This fault, located on the southeastern margin of the Qinghai‒Tibetan Plateau, plays a key role in the extrusion, rotation and escape of the continental blocks constituting the Qinghai‒Tibetan Plateau. Furthermore, this fault represents the southwestern boundary of the Sichuan–Yunnan Block, which has experienced strong deformation and frequent seismic activity. The northern segment of the Red River Fault Zone is the most active part of the whole fault. However, surface erosion and vegetation coverage have obscured the activity of the northern segment; therefore, the study of its activity has obviously been insufficient. There is still controversy over whether all the secondary faults on the northern segment are active Holocene faults. Studying the activity characteristics of the northern segment, which is densely populated, is particularly important for seismic risk prevention in this area. Based on remote sensing interpretations and field geological surveys, this paper describes the latest activity characteristics of the Cangshan Piedmont Fault, Fengyi–Dingxiling Fault and Midu Basin Margin Fault, including their spatial distributions and kinematic characteristics. According to the ages of the offset strata in profiles, the above three secondary faults were all active in the late Holocene. The latest active age of the Cangshan Piedmont Fault was later than 543-494 cal BP, and two palaeoseismic events that occurred in this section during the Holocene occurred at 2700 and 473 cal BP. The latest active age of the Fengyi–Dingxiling Fault was later than 2760–2700 cal BP; in this section, one Holocene palaeoseismic event occurred between 1777 cal BP and 2730 cal BP, another occurred between 2730 cal BP and 5664 cal BP, and the third occurred between 6449 cal BP and 8360 cal BP. The latest active age of the Midu Basin Margin Fault was later than 558-510 cal BP, and two Holocene palaeoseismic events occurred later than 2318-2114 cal BP and 558-510 cal BP. Based on the results of this paper and previous studies, we believe that the Fengyi–Dingxiling Fault on the northern segment of the Red River Fault Zone is at risk for future strong earthquakes. Additionally, abundant geological and geomorphologic evidence suggests that the northern segment is dominated by normal faults, reflecting the local strain response to secondary clockwise rotation of the Sichuan–Yunnan Block along the boundary fault. This finding is in line with the eastwards extrusion and escape of materials on the Qinghai‒Tibetan Plateau caused by the northwards and northeastwards pushing of the Indian Plate. To a certain extent, these observations reflect the tectonic deformation coordination between block rotation and boundary fault slip in the Sichuan–Yunnan Block in the context of continental block extrusion on the Qinghai–Tibetan Plateau.

Effect of the Kahramanmaraş earthquake on standing water tanks in the Adana region and buildings in Hatay-Antakya

It is known that the devastating earthquakes experienced in Türkiye in recent years have caused significant loss of life and structural damage throughout the country. Especially the large-scale earthquakes that occurred in Kahramanmaraş on February 6, 2023 and the effects of these earthquakes are examined in detail by researchers. In post-earthquake inspections, it is emphasized that structures such as hospitals and water tanks that need to provide emergency services after the earthquake should be examined in detail and that these structures should be earthquake resistant. In this study, while material-related damages in the structures in the regions affected by the Kahramanmaraş earthquake are examined, the importance of structural improvements, especially in order to increase the earthquake resistance of water tanks, is emphasized. It was also stated that the reasons for the building collapses that occurred after the earthquake in Hatay were discussed in detail. This study makes a valuable contribution to increasing the durability of structures in earthquake risk areas.

Structural Stability Evaluation of Natural Fiber Retrofitted Low-Cost Rammed Earthen Houses Under Seismic Loading

Earthen houses constructed using the rammed technique have long served for housing across the globe. However, despite their environmental benefits, these houses may pose unacceptable earthquake risks for the communities. To address this, the current study focuses on investigating the seismic response of unreinforced and retrofitted rammed earth model houses using unidirectional shaking table experiments. Retrofitting is performed using two different approaches. The first method is the traditional way using cement, lime and natural fibers like straw and jute mixed with soil. The second method is a new and innovative approach that uses bitumen-treated natural fibers such as jute and bamboo strips as external encasing reinforcement along with special L-shaped corner reinforcement using jute and bamboo sheets. The study shows that rammed earth houses retrofitted using the proposed novel and low-cost methods with jute/bamboo fibers demonstrate promising results in terms of structural strength and ductility compared to the stabilized counterpart. The fundamental period of the retrofitted and unreinforced houses is found in the order of 0.08 and 0.12 indicating an enhancement in lateral stiffness depending on various level retrofitting methods. The study provides valuable insights and points toward potential changes in the seismic design guidelines for low-cost rammed earthen houses.

Earthquake And Landslide Disaster Risk Assessment At The University Of Defense: A Preliminary Study

The geographical location of the University of Defense in Bogor Regency, Citereup Sub-district, Bogor, West Java, is a sloping terrain that can potentially cause landslides. The InaRISK map released by BNPB, shows that the Defense University is located in an area of Bogor Regency that is prone to disasters, especially landslides. Disaster risk assessment is an approach to show the potential negative impacts that may arise due to a potential disaster. The potential negative impacts are calculated based on the level of vulnerability and capacity of the area. This potential negative impact is seen from the potential number of people exposed, property loss, and environmental damage (PERKA BNPB, 2012). Researchers conducted an analysis of landslide and earthquake disaster vulnerability at the University of Defense. A study of building and population vulnerability to potential earthquakes and landslides was conducted at the University of Defense. The components of social vulnerability at the University of Defense in the event of an earthquake and landslide were obtained. Researchers obtained data on population capacity and building conditions at the University of Defense. Landslide and earthquake disaster risks have the potential to occur at the University of Defense. The University of Defense has the potential threat of landslides because the buildings of the University of Defense are located on hilly slopes. The vulnerability of the University of Defense buildings, the University of Defense buildings have not been designed to be entirely earthquake resistant. This can be seen in some buildings that have visible cracks. It is necessary to retrofit or strengthen the foundations of buildings in the Defense University area that have experienced a decrease in performance such as cracking, shifting, displacement. An important component where the University community and students need self-protection and rescue skills through training.

Hybrid seismic vulnerability models for regional structures considering bivariate intensity measures

The multiple-probability decision-making method for earthquake hazards considers multiple performance indicators and can be used to effectively estimate the seismic risk of structures. The seismic vulnerability model directly affects the development of the earthquake risk distribution in regional structures. This paper innovatively developed a bivariate intensity measurement method based on macroscopic and instrumental seismic intensities. An optimized instrument intensity calculation model was established considering the actual monitoring data of historical earthquakes in China. A hybrid seismic vulnerability quantification method based on empirical, expert judgement and analysis has been proposed and applied to evaluate the vulnerability levels of three types of building clusters in two typical earthquakes in Qinghai Province, China (the 2008 Dachaidan (DCD) earthquake and the 2009 Haixi (HX) earthquake). A structural hybrid vulnerability matrix and surface for nine zones based on bivariate intensity measures were developed. A synthetic vulnerability membership index considering fuzzy failure criteria and decision theory was proposed, and vulnerability membership curves for different vulnerability levels were established. An improved earthquake economic loss prediction function is proposed, and synthetic economic vulnerability index prediction models for three typical buildings in different regions are established. The estimated and calculated results of the developed multiscale variable parameter synthetic vulnerability model are highly consistent with the actual earthquake loss observations.

Understanding the Contribution of Conventional Media in Earthquake Risk Communication

To mitigate the damage from and prepare for disasters, individuals and communities should be involved in the disaster risk reduction efforts. Communicating the risk effectively is the essential step of this involvement. Risk communication is a multidisciplinary field. Disaster managers have to work closely with the media, among other partners, but there is a gap in their understanding of each other’s roles. This study aims to explore the process of publishing and broadcasting earthquake information through the experiences of media professionals, to understand how journalists and news organizations function before and after disasters, and to provide evidence to help bridge the gap between disaster managers and/or public health authorities and disaster journalists and/or news organizations., especially in earthquake preparedness. Thirteen in-depth interviews were conducted with editors/journalists from national newspapers and TV channels. A good context for investigating these issues is afforded by the megacity Istanbul and the Turkish media. Turkey is a land of earthquakes. A further strong earthquake is expected to hit in the near future. The findings, which gave valuable hints for better collaboration, are presented according to the focus of the question guide: time of and norms for publishing or broadcasting news or information about earthquakes; content of the news or information; disaster journalism and guidelines.

Analysis of tough clay soil plastic index from several quarries in Aceh Besar District for seismic mitigation

Abstract Clay soils that tend to have the potential for landslides and earthquake-induced cracking are a serious problem in the development of infrastructure and settlements in the area. This research investigation sample was collected at a quarry in several areas of Aceh Besar District to identify problematic soil behavior in various quarries. The method used was stabilization by conducting compaction testing to obtain the optimum moisture content of the natural soil. The quarry soil samples taken were disturbed samples, which were then tested directly at the Soil Mechanics Laboratory. The data used in this study is the plastic index (PI) value. This research aims to assess stabilization strategies for problematic clay soils as an earthquake risk mitigation effort in the Aceh Besar region. The results of this study are expected to provide practical guidance for stakeholders in planning and developing more earthquake-resistant infrastructure in Aceh Besar. The result of the test showed that the OMC value was 36.3% with a dry weight of 1.22 gr/cm3.

Earthquake Risk Analysis as a Disaster Mitigation-Based Spatial Planning Strategy in the National Tourism Strategic Area of Kolorai Village, Morotai Island

Kolorai Village is a National Strategic Tourism Area (KSPN) influenced by complex tectonic activity. The low community resilience to earthquake disasters in Kolorai Village means that the government must refrain from using disaster risk factors as a reference in developing disaster mitigation-based tourism areas. This research aims to analyse the risk of earthquake disasters in the tourism area of Kolorai Village. Problem-solving in this research uses the survey method and descriptive analysis with a quantitative approach. Primary data or field data in the form of vulnerability and capacity data are obtained using the help of checklist instruments, questionnaires, and interviews. The earthquake disaster risk analysis results in Kolorai Village have a score of 3. They are included in the high category with a percentage of hazard factors of 43%, 28% vulnerability, and 29% capacity. The value of earthquake disaster risk is produced as a map that illustrates the elements of earthquake disaster risk in the Kolorai Village Tourism Area. So that it can be used for spatial planning, it needs to be integrated with disaster risk reduction.

Monte Carlo Based Sampling Distribution of Annual Rate of Exceedance for Earthquake Insurance

ABSTRACT Seismic hazard expressed in terms of annual rate of exceedance and is used to calculate the earthquake insurance premium. Annual rate of exceedance is a complicated function of magnitudes, distances from site to earthquake sources and attenuation. Due to its complexity, determination of exact sampling distribution of earthquake insurance premium is not an easy task. This research proposes Monte Carlo simulation approach to determine the sampling distribution of earthquake insurance premium. Annual rate of exceedance was simulated first and then the insurance premium calculated based on simulation of annual rate of exceedance. The simulation involves quantifying synthetic catalogue similar to historical catalogue. Its simulation is conducted in order to construct annual rate of exceedance as an indicator of earthquake risk used in earthquake insurance. The simulation of 25 iteration and sample size of 100 shows that the sampling distribution of insurance premium is skewed to the right. The idea of using Monte Carlo simulation to study the sampling distribution of annual rate of exceedance is the originality of the study and the study contributes to the methodology of earthquake insurance.

Earthquake Risk Assessment in Seismically Active Areas of Qinghai Province Based on Geographic Big Data

Earthquakes can cause serious damage to buildings, roads and other infrastructure. The large amount of dust and particulate matter generated when these structures collapse and are damaged can quickly enter the air, leading to a decline in air quality. At the same time, earthquakes may cause secondary disasters such as fires and landslides, which will also produce large amounts of soot and particulate matter, which will have a negative impact on air quality. Therefore, earthquake disaster risk assessment studies are carried out to identify potentially hazardous areas and facilities in advance in order to reduce the air pollution problems that may be caused by earthquakes. Existing research on earthquake disaster risk assessment mainly evaluates earthquake risk from the perspective of geology or seismology, but there are few studies based on multidisciplinary assessment that integrates geology, seismology, engineering and social sciences into socioeconomic factors. To this end, based on remote sensing and GIS technology, this paper takes Qinghai Province, a seismically active area, as the research area, and integrates land use data, natural environment data, social environment data and seismic parameter zoning data to construct a comprehensive assessment model for earthquake disaster vulnerability and risk. The results showed that there were 5 very high-risk areas, 7 high-risk areas, 10 medium-risk areas, 11 low-risk areas and 12 very low-risk areas in Qinghai Province. The high-risk areas are mainly distributed in the central and western parts of Qinghai Province, where the earthquake breeding environment is sufficient, the scale of active faults is huge and the adaptability of the carrier is low. The results of an earthquake disaster risk assessment can provide a reference for the government to formulate environmental protection policies. According to the assessment results, the government can formulate targeted measures to strengthen air pollution control and improve air quality.

Climate Change-induced Livelihood Insecurity in Narayani-Gandak Basin of Nepal

Nepal is one of the most disaster-prone countries in the world. Nepal is highly vulnerable to climate risks and disasters. It ranks 4th, 11th, and 13th in terms of vulnerability to climate change, earthquake, and flood risks, respectively. Due to intensive, concentrated, and erratic precipitation, climate change-induced disasters such as 'too much water and too little water' are rapidly increasing in Nepal and the ‘too much water’ has been affecting riverine communities, significantly, in the Terai region of Nepal. The communities of the Narayani basin have been forced to encounter floods every year due to the perennial Narayani and Rapti including other local seasonal rivers. While these rivers seem to b e providing services for irrigation to nurture agricultural products, to some extent, the riparian communities have also been forced to encounter extensive amounts of losses and damages to lives, livestock, crops, and property, which have resulted in losses of livelihoods, and generated serious concerns for communities due to surmounting risks of flood like natural hazards turning into disasters. Employing a mixed-method research approach, we investigated how climate change-induced hazards such as floods turning into disasters have affected the livelihoods of people living in the riverine communities of Chitwan. The two research objectives we explored were i) to examine the impacts of climate change and floods on agriculture and the livelihoods of community people, and ii) to investigate the adaptive methods adopted by local communities to combat climate change-induced flooding for building climate/flood resilient communities. The findings of the research demonstrated that climatic changes have interacted with socio-economic and agricultural practices and significantly affecting livelihood of the communities in Chitwan. In response to changing climatic conditions and unanticipated weather patterns, people in the communities are gradually adjusting their agricultural practices, covering the losses and damages through insurance policies and diversifying the income generating sources.

SPATIAL INSIGHTS INTO EARTHQUAKE STRENGTH: A SULAWESI CASE STUDY USING ORDINARY AND ROBUST KRIGING METHODS

The data from the Meteorology, Climatology and Geophysics Agency (BMKG) in the last 22 years shows that there have been 230 destructive earthquakes in Indonesia with the highest incidence in 2021. One of the islands frequently hit by earthquakes is Sulawesi Island. According to the 2020 Disaster Risk Index Book (IRBI), 63 of the 81 regencies/cities on Sulawesi Island have a high category earthquake risk index. Based on this, information is needed as a first step in disaster mitigation so that the government can take preventive and anticipatory actions to reduce risks associated with earthquakes and ensure the safety of people on the island of Sulawesi, one of which is obtained through spatial interpolation. In this study, the Kriging methods of interpolation, Ordinary Kriging (OK) and Robust Kriging (RK) were used. From the analysis with OK and RK, the best theoretical semivariogram model is the Exponential model with nugget, sill and range values of ​​respectively 0.40, 0.70, and 6.50 for OK and 0.35, 0.90 and 9.50 for RK. Both methods produced the results that most areas of Sulawesi Island have the potential for shallow earthquakes with a magnitude of around 3.2 to 4.0 on the Richter scale. The potential for earthquakes with high strength is more common around the seas to the east and north of Central Sulawesi Province. The highest estimation results are at the coordinates of 120,029° East Longitude, 1.159° North Latitude, namely in the sea north of South Dampal. According to the results of K-Fold Cross Validation and Leave One Out Cross Validation, the more accurate method for estimating earthquake strength on Sulawesi Island is the RK method because the RMSE and MAPE values ​​in the RK method are smaller than the OK method.

1 g shake table study on seismic strengthening of low-cost rammed earthen houses built of silt enriched soil using natural fiber reinforcement

Earthen houses are practiced as a traditional and low-cost housing in many countries around the globe. These houses were exposed to unacceptable earthquake (EQ) risks despite their environmental benefits. Past earthquakes including the recent past 2017 Tripura EQ has evidenced significant damages mostly in earthen/masonry houses which are built in a non-engineered manner. In this context, the current study aims to investigate the seismic behavior and failure patterns of both unreinforced and using proposed retrofitted rammed earth model houses (with and without openings) built using typical Tripura soils having higher silt content using unidirectional shake table experiments on total 26 physical models. Besides, both seismic strength and structural stability are also examined for retrofitted earthen houses. The study indicates that, proposed novel low-cost natural fiber made textile encasing reinforcement technique has exhibited promising seismic performance of such houses from the view point of structural strength and ductile behavior as compared to traditional cementitious additives and fiber blended stabilized retrofitted houses as well untreated houses. The fundamental lateral period of model unreinforced and reinforced houses found within the range of 0.08 to 0.15 s respectively which indicates increased stiffness of walls due to strengthening may decrease the lateral period maximum up to 46.67%. On the other hand, the maximum increase in seismic strength was observed in order of 4.50 to 6.31 times in the case of bitumen treated bamboo fiber textile based encased houses with L-shaped bamboo splint corner reinforcement whereas traditional cementitious stabilized method has offered maximum 1.13 to 1.83 times increment in lateral strength. Further, the effect of different parametric variations such as area of openings (doors and windows), thickness to height ratio, variation in compaction methodologies on seismic performances of unreinforced rammed earthen houses were also studied in detail. Finally, regression based closed form predictive expressions for seismic strength of rammed earthen houses and without retrofitting are proposed herein. The performed cost analysis study will also help to assess the effectiveness of proposed strengthening techniques.

The effect of sand-crumb rubber mixture treatment on the seismic response of a low-rise building located on liquefiable soil

One of the most effective measures to reduce earthquake risks in high-seismic areas is to reduce the input forces caused by earthquakes to the structure. The properties of rubber materials in geotechnical projects are energy absorption, dynamic deformation change as well as damping of latent energy in loads, high shear modulus and damping ratio, easy access and their economic nature. In this research, with finite difference modeling, the effect of using sand- crumb rubber layer on the seismic behavior of the model has been obtained. In the following, by changing the thickness and depth of the sand-crumb rubber layer, the seismic behavior such as floor displacement and internal forces have been investigated. This research numerically models liquefaction (UBCsand with FLAC) and predicts the effects of the sand-crumb rubber layer of different thicknesses (as % weight of the mixture) under the foundation and evaluates the structure's damage and settlement interacting with the soil by validating the numerical model with the laboratory model and calibrating it with different ratios. The results show that liquefaction, pore water pressure excess ratio and soil settlement will be significantly reduced with the presence of sand-crumb rubber layer, and also the base shear has shown an increase, but the structural damage is reduced.Graphical

Towards Sustainable Urban Transformation: The Role of LEED Certification in Istanbul's Future and Economy

Istanbul, a city with a rich history and vibrant culture, faces the imminent threat of a catastrophic earthquake due to its proximity to the North Anatolian Earthquake Fault. In response, the Turkish government has initiated a sweeping urban transformation led by the Ministry of Environment and Urbanization. This initiative aims to not only rebuild the city but also to enhance its resilience to earthquakes and environmental challenges. Central to this transformation is the adoption of green building principles, particularly LEED (Leadership in Energy and Environmental Design) certification. LEED provides a comprehensive framework for sustainable building design, construction, and operation, encompassing categories such as Sustainable Sites, Water Efficiency, Energy and Atmosphere, Materials and Resources, Indoor Environmental Quality, Innovation, and Regional Priority. This paper examines the economic and future considerations of enforcing green certification during Istanbul's urban transformation. Through a detailed analysis of the costs and benefits of LEED certification across different categories, as well as alternative approaches to sustainability, this paper aims to provide a holistic view of the implications for Istanbul's economic landscape and long-term prospects. By integrating environmental sustainability into its urban renewal efforts, Istanbul has the opportunity to not only mitigate the risks of earthquakes but also to emerge as a model for sustainable, environmentally conscious urban development. This paper seeks to highlight the importance of green certification in shaping Istanbul's urban landscape for generations to come, with a focus on economic considerations, environmental impacts, and broader implications for the city's future.

Eigenvector spatial filtering enhancing natural hazards vulnerability assessment in a susceptible urban environment: A case study of Izmir earthquake in Turkey

The increasing risk of earthquakes in urban areas has made it crucial to develop accurate vulnerability models for city infrastructure and systems. We aimed to assess and compare the effectiveness of different models and vulnerability analysis techniques in predicting earthquake vulnerability in the specific context of Izmir, Turkey. One central hypothesis in this research aimed to determine whether integrating Eigenvector Spatial Filtering (ESF) into both regression models and machine learning algorithms would yield a comparable enhancement in model performance. We performed earthquake vulnerability modeling (EVM) by considering (ⅰ) only seismic-related variables (SRV) and (ⅱ) integrating ESF by using Moran's eigenvector maps (MEMs). For each approach, we evaluated the predictive performance of two simple regression-based models; generalized linear model (GLM) and generalized additive model (GAM), and two complex machine learning ones; generalized boosting model (GBM), and random forest (RF). The study utilized five primary indicators encompassing geotechnical, physical, structural, social, and facilities data. The predictive performance of the models was assessed using evaluation metrics including Root Mean Square Error (RMSE), Mean Absolute Error (MAE), and adjusted R2. The results indicated that the optimal candidate model consisted of five key variables: altitude, building height, distance to safety gathering places, Peak Ground Acceleration (PGA), and population density. We found that decision-tree-based methods performed better than regression-based methods for both modeling schemes. RF exhibited the highest predictive performance for the training data (RMSE = 0.59, adjusted R2 = 0.71), while GBM outperformed other models for the test data (RMSE = 0.79, adjusted R2 = 0.78). However, incorporating ESF to the EVM analysis revealed that regression-based methods, particularly the GLM, obtained highest improvement in accuracy (RMSE 0.94 vs 0.76 and adjusted R2 0.56 vs 0.71 for the SRV and SRV + MEMs modeling approach). Significant differences were observed between GLM-GBM and GLM-RF comparisons, as well as GAM-GBM and GAM-RF comparisons. The findings of this research are expected to be helpful for informed decision-making, targeted risk reduction, and the development of effective policies and strategies to enhance preparedness and resilience in the face of seismic events in highly susceptible urban systems.