Search Results (129)

In the earthquakes that occurred in the Pazarcık (Mw = 7.7) and Elbistan (Mw = 7.6) districts of Kahramanmaraş Province on 6 February 2023, many buildings collapsed in the Hayrullah neighborhood of the Onikişubat district. In this study, we investigated whether there was a soil amplification effect on the damage occurring in the Hayrullah neighborhood of the Onikişubat district of Kahramanmaraş Province. Firstly, borehole, SPT, MASW (multi-channel surface wave analysis), microtremor, electrical resistivity tomography (ERT), and vertical electrical sounding (VES) tests were carried out in the field to determine the engineering properties and behavior of soil. Laboratory tests were also conducted using samples obtained from bore holes and field tests. Then, an idealized soil profile was created using the laboratory and field test results, and site dynamic soil behavior analyses were performed on the extracted profile. According to The Turkish Building Code (TBC 2018), the earthquake level DD-2 design spectra of the project site were determined and the average design spectrum was created. Considering the seismicity of the project site and TBC (2018) criteria (according to site-specific faulting, distance, and average shear wave velocity), 11 earthquake ground motion sets were selected and harmonized with DD-2 spectra in short, medium, and long periods. Using scaled motions, the soil profile was excited with 22 different earthquake scenarios and the results were obtained for the equivalent and non-linear models. The analysis showed that the soft soil conditions in the area amplified ground shaking by up to 2.8 times, especially for longer periods (1.0–2.5 s). This level of amplification was consistent with the damage observed in mid- to high-rise buildings, highlighting the important role of local site effects in the structural losses seen during the Kahramanmaraş earthquakes. Full article

An expanded Pacific Earthquake Engineering Research (PEER) Center Next Generation Attenuation Phase 2 (NGA-West2) ground motion database, compiled using shallow crustal earthquakes in active crustal regions (ACRs), was used to develop the closed-form GS24b backbone ground motion model (GMM) for the RotD50 horizontal components of peak ground acceleration (PGA), peak ground velocity (PGV), and 5% damped elastic pseudo-absolute response spectral accelerations (SA). The GS24b model is applicable to earthquakes with moment magnitudes of 4.0 ≤ M ≤ 8.5, at rupture distances of 0 ≤ $R_{rup}$ ≤ 400 km, with time-averaged S-wave velocity in the upper 30 m of the profile at 150 ≤ $V_{S30}$ ≤ 1500 m/s, and for periods of 0.01 ≤ T ≤ 10 s. The new backbone model includes $V_{S30}$ site correction developed based on multiple representative S-wave velocity profiles. For crustal wave attenuation, we used the apparent anelastic attenuation of SA—Q_SA (f, M). In contrast to the GK17, the GS24b backbone is a generic ACR model designed specifically to be adjusted to any ACRs. The GS24bc is an example of a partially non-ergodic model created by adjusting the backbone GS24b model for magnitude M, S-wave velocity $V_{S30}$, and fault rupture distance residuals. Full article

This work presents an analysis of the sub-ionospheric VLF transmitter signal disturbances which were detected more than one week before the Turkey–Syria EQ occurrence. We have applied the multi-terminator method when considering amplitude and phase variations of the TBB transmitter signal (Turkey), selected because of a good signal to noise ratio for the amplitude, a stable phase variation, and a ray-path propagation crossing the pre-seismic sensitive region, estimated from the combination of the Dobrovolsky area and the Fresnel zone. New spectral features, i.e., inflexions and jumps, are considered in this study, besides the minima and maxima investigated in. The spectral occurrence probabilities are derived at three specific locations: Graz facility, TBB station and EQ epicenter. We show that two main precursors occurred from 27 to 30 January, and from 31 January to 3 February. More important are the prior precursors detected from 23 January to 25/26 January, where anomaly fluctuations were found to be similar to those at the EQ epicenter area, approximately. A forecasting model is proposed, in which the main steps can provide, in the presence of spectral anomalies, first hints regarding the longitudinal locations of the seismic preparation zone. Full article

In early 2025, the Santorini–Amorgos area (Aegean Volcanic Arc, Greece) experienced a seismic swarm, with dozens of M ≥ 4.0 earthquakes and a maximum magnitude of M = 5.2. Beyond its seismological interest, the sequence was notable for triggering rare increased preparedness actions by Greek Civil Protection operational structures in anticipation of an imminent destructive earthquake. These actions included (i) risk communication, (ii) the reinforcement of operational structures with additional personnel and equipment on the affected islands, (iii) updates to local emergency plans, (iv) the dissemination of self-protection guidance, (v) the activation of emergency alert systems, and (vi) volunteer mobilization, including first aid and mental health first aid courses. Although it was in line with contingency plans, public participation was limited. Volunteers helped bridge this gap, focusing on vulnerable groups. The implemented actions in Greece are also compared with increased preparedness during the 2024–2025 seismic swarms in Ethiopia, as well as preparedness before the highly anticipated major earthquake in Istanbul (Turkey). In Greece and Turkey, legal and technical frameworks enabled swift institutional responses. In contrast, Ethiopia highlighted the risks of limited preparedness and the need to embed disaster risk reduction in national development strategies. All cases affirm that preparedness, through infrastructure, planning, communication, and community engagement, is vital to reducing earthquake impacts. Full article

The main causes of damage include poor site selection, such as building on fault lines or on fill soil, as well as deficiencies in design, materials, and workmanship. Damage levels are also linked to the economic conditions of the region. In the 1939 earthquake, there were high casualties due to the magnitude of the earthquake, lack of engineering design in traditional structures and unsuitable soil conditions. Similarly, in the 1992 earthquake, unexpected damage occurred due to faulty designs created by inexperienced engineers who lacked sufficient knowledge of the seismic behavior of structures, errors in craftsmanship and workmanship, and unsuitable residential area selection for construction. These problems continue today and put most of the building stock at risk in case of a major earthquake. Seismic steel isolators are used in two new buildings in the city; if they are effective, they should be made mandatory in new construction. Otherwise, consideration should be given to relocating the city to the more stable southern rocky areas, which were unaffected in both 1939 and 1992. Full article

This study evaluates the seismic fragility and code compliance of reinforced concrete buildings in Turkey following the 6 February 2023 Kahramanmaraş earthquake. Sixty representative buildings were modeled in SAP2000, consisting of thirty structures designed according to TEC-1975 and thirty according to TEC-1998. These models were subjected to three-dimensional nonlinear time history analyses using ground motions scaled to match the seismic characteristics of the earthquake. Structural performance was assessed by comparing calculated displacement demands with capacity thresholds defined by modern code provisions. The results show that buildings designed under TEC-1998 generally performed better than those constructed according to TEC-1975, particularly in terms of deformation capacity and collapse resistance. Fragility curves and exceedance probabilities were developed to quantify damage likelihoods across different performance levels. When compared with post-earthquake field observations, the analytical models produced lower collapse rates, which may suggest the presence of widespread code noncompliance in the actual building stock. These findings highlight the critical importance of ensuring adherence to seismic design regulations to improve the resilience of existing structures. Full article

Background: This study aimed to analyze the challenges faced by professionals and volunteers in search and rescue operations after the earthquake that struck the southeastern region of Turkey, with its epicenter in Kahramanmaraş, on 6 February 2023. Method: This research was conducted using a qualitative approach; specifically, a phenomenological method. It presents the results of semi-structured individual interviews with eight sampled volunteers who participated in the search and rescue activities following the earthquake. Participants were between the ages of 24 and 45, and three were nurses, three were journalists, and two were civilian volunteers with no formal training in search and rescue. In terms of nationality, five participants were citizens of the Turkish Republic of Northern Cyprus (TRNC) only, while three had both TRNC and Turkish citizenship. Field duties included providing medical support, documenting incidents, and assisting survivors in collaboration with civil society organizations. The research data were analyzed using MAXQDA Analytic Pro 2020. Results: Within the scope of this research, four main themes and twenty-one sub-themes were identified. The first theme is related to the nature of the traumatic events and reflects the characteristics of the traumatic experiences of the participants. The second theme is secondary trauma symptoms, showing that the participants experienced symptoms such as overstimulation, intrusive thoughts, sleep problems, anger, and concentration difficulties. The third theme focuses on post-traumatic growth symptoms. Participants reported experiencing developmental changes following trauma, such as changes in self-perception, the ability to recognize new situations, understanding the value of life, and positive relationships related to personal growth. Finally, the fourth theme is related to the coping skills used to cope with traumatic events; participants shared their coping strategies and the impact of these strategies. Conclusions: This study highlights the need to assess individuals in search and rescue operations in terms of secondary trauma. Our findings may be used as a reference to develop post-disaster psychosocial support services for volunteer search and rescue teams. Additionally, the findings can be used to renew the content of pre-field preparation training. Full article

The 6 February 2023 earthquake in Kahramanmaraş, Turkey, caused significant debris accumulation, raising concerns about air quality and public health. This study assessed dust concentrations during debris removal and emergency response efforts over a five-day period. Post-disaster respirable and total dust concentrations were measured using dust monitoring devices and the MDHS-14/3 gravimetric method. Scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analyses identified fibrous structures and elements associated with asbestos, suggesting potential long-term health risks such as asbestosis and lung cancer. The average respirable dust concentration was 30.84 mg/m³, and the total dust concentration was 33.66 mg/m³. The findings emphasize the urgent need for protective measures to mitigate exposure risks for affected populations and emergency responders. Integrating health risk assessments into disaster management strategies are crucial to reducing long-term public health impacts. Full article

This paper utilises teleseismic Z-component data to investigate rupture propagation, extent, and velocity for two very destructive earthquakes in the East Anatolian Fault Zone (EAFZ): the $M_w$ = 7.8 earthquake near Kahramanmaras and the largest ($M_w$ = 7.5 s) aftershock at Elbistan (both on 6 February 2023). The extent of the rupture is modelled with beamforming and multichannel signal classification. The teleseismic data are derived from agencies in USA and Canada. The rupture of the $M_w$ = 7.8 earthquake is found to be bi-directional towards the northeast and southwest. Three rupture segments are identified for the Kahramanmaras earthquake between 34.5°–37.5° longitude and 37.0°–37.5° latitude, and another three are identified for the Elbistan earthquake between 36.5°–38.0° longitude and around 38.5° latitude. A total of 299 km is covered in 185 s with rupture velocities between 3.1 km/s and 3.4 km/s. Additionally, the mainshock’s splay and the second-largest aftershock’s rupture are also bidirectional, covering 150 km within 46 s. Five velocity segments are identified, three for the Kahramanmaras and two for the Elbistan earthquakes. Beamforming is efficient for identifying the velocity segments. The findings provide new insights on the evolution of the spatio-temporal rupture of the EAFZ and may serve as a basis for long-term earthquake hazard planning in the area. Full article

The catastrophic twin earthquakes that struck southern Turkey and northern Syria on 6 February 2023 caused massive casualties and extensive damage to infrastructure, with Hatay Province of Turkey bearing the brunt of the impact. To swiftly and thoroughly assess the damage caused by the earthquakes and the subsequent reconstruction efforts, this study initially investigated the application of light change ratios between the pre-earthquake monthly nighttime lights (NTLs) and the post-earthquake daily NTL data to identify earthquake damage in Hatay Province. Next, the monthly NTL data were employed to calculate the time series average lighting index (ALI). Subsequently, random noise and seasonal fluctuation were eliminated through data smoothing and seasonal decomposition techniques. Pre- and post-earthquake regression models were then utilised to establish a comprehensive framework for assessing economic recovery following the earthquake. The findings indicated that (1) the seismic damage identification method based on NTL data achieved an overall accuracy exceeding 71.55% in detecting building damage after a disaster. This method provided a swift and effective solution for rapidly assessing disaster-related destruction. (2) The reduced NTLs exhibited a strong correlation with the area of severely and moderately damaged buildings while showing a weaker correlation with areas of slightly damaged buildings. (3) The developed pre- and post-earthquake regression models demonstrated a high degree of fit, making them valuable tools for assessing regional economic recovery after the earthquake. At the county scale, such districts as Erzin and Kumlu exhibited promising signs of recovery, while such severely impacted areas as Antakya faced misconceptions of progress, primarily due to the brightening of NTLs caused by reconstruction efforts. Additionally, such districts as Dortyol and Samandag grappled with substantial short-term recovery challenges. Although the province experienced gradual economic recovery, achieving complete restoration has remained complex and time-intensive. The study offers valuable insights into earthquake damage assessment and economic recovery monitoring while serving as a scientific reference for disaster mitigation and post-disaster reconstruction efforts. Full article

The behavior of the soils under dynamic loads is of great importance for the structures to be built in earthquake zones. As a result of the determination of the site-specific dynamic parameters of the soils and the analyzes to be made with these parameters, the ground response that will occur on the surface during the earthquake will be determined. Turkey is located in one of the important earthquake belts of Europe. Studies are carried out on the North Anatolian Fault Zone (NAFZ), which is one of the important and active fault lines here. In this study, as a result of 4 drilling studies on NAFZ, firstly, dynamic triaxial (TRX) and resonant column (RC) test systems were used to obtain site-specific shear modulus and damping curves depending on depth. 11 earthquake acceleration records reflecting the seismic characteristics of the region were selected and scaled in both time-history and frequency-time domains. Two different scaling methods were compared with the nonlinear soil amplification analysis. In addition, surface response spectra were examined according to the Turkish Building Earthquake Code (TEC 2018). Although there is not a big difference in amplification values in two different scaling methods, it has been determined that the design spectrum values are very different. Full article

This article presents the results of a study conducted to obtain the fragility curves of an existing reinforced concrete highway bridge in Kocaeli, Turkey, to investigate the collapse potential. Bridges are key components of transportation systems, providing convenient and efficient access to different locations. However, these structures are susceptible to forces that can cause significant damage in the event of seismic activity. Thus, the fundamental target of designing earthquake-resistant bridges is to ensure that they can remain functional at an acceptable level during seismic activity. At least, they are expected to survive strong earthquakes without collapse. Turkey is a country located on active fault lines and has experienced devastating earthquakes in the past. This high earthquake risk requires the design and construction of bridges that are a critical part of the transportation infrastructure having adequate safety levels so that the collapse risk can be minimized. Therefore, damage estimation of bridges is an important part of earthquake preparedness and the response plans that will be followed immediately after earthquakes. In this study, the fragility curves of an existing reinforced concrete highway were obtained to investigate the collapse potential. The interstory drift limits related to the performance levels defined by the Turkish Bridge Seismic Design Code 2020 were determined by the incremental dynamic analysis method, and fragility curves were obtained using 10 different earthquake records based on these determined limits. The results showed that the target performance level Uninterrupted Occupancy and Collapse Prevention performance level requirements, as defined by the Turkish Bridge Seismic Design, were not met, and the Collapse Probability is %100. Full article

Two large earthquakes with a series of aftershocks struck southeastern Türkiye within 9 h and had catastrophic consequences. Following the earthquake doublet, 11 provinces corresponding to approximately 1/7 of Türkiye were declared disaster zones. Even though the epicenters of the first event and second mainshocks were in Pazarcik and Elbistan with a magnitude ($M_w$) of 7.7 and 7.6 with over 500 km of multiple-fault ruptures, Hatay province was the most heavily damaged province and had the highest number of casualties and collapsed buildings. A densely deployed strong ground motion array of the Disaster and Emergency Management Presidency of Turkey (AFAD) recorded the earthquake doublet of the two consequent mainshocks, including ground motions exhibiting near-fault features. A suite of recorded ground motions in Hatay province is incorporated to examine the destructiveness of ground motions on reinforced concrete Moment-Resisting Frame buildings and the effectiveness of seismic isolation technology to reduce the observed damage. Moreover, Turkish Seismic Design Code-2018 code provisions are elaborated to determine the characteristics of the investigated structures. Nonlinear response history analyses were conducted for 24 types of structures by following the design provisions. The inelastic hysteretic response features in the fixed-base and isolation systems are represented through an inelastic Single-Degree-of-Freedom Bouc–Wen hysteretic model. Extreme characteristics of near-fault ground motions on RC structures and seismically isolated systems resulted in excessive drift and displacement demands. Roof drifts of reinforced concrete Moment-Resisting-Frame buildings exceeded 4% roof drift in mid-rise buildings, compatible with the field observations in Antakya city center, where the displacement demand and ultimate base shear coefficient of seismically isolated structures considered in this study exceeded the elastic spectral coefficient values of the design spectrum in the proximity of fault ruptures. Full article

The external walls of a building represent the interface between the interior and exterior environments. Insulating external walls represents the most cost-effective means of ensuring indoor comfort. Despite the prevailing assumption that insulation will increase the cost of the building, this study has demonstrated that this is not the case. Notwithstanding the increase in investment costs, the application of insulation to the external walls has been demonstrated to result in a reduction in fuel consumption and operating costs. In accordance with TS 825, there are five distinct degree-day zones, with the requisite heat loads in these zones exhibiting variability. Accordingly, a cost-based methodology is required to ascertain the optimal insulation thicknesses for the various degree-day zones. In this study, the gains to be obtained in the case of using three different insulation materials for five different wall types to be used in the buildings to be built instead of the buildings destroyed in the earthquake in Turkey in 2023 were analyzed. Samples from three degree-day zones affected by earthquakes were assessed for insulation, wall structures, and fuel types. The study assesses optimum insulation thickness, investment cost, annual fuel savings, annual economic benefits, and investment payback period. Full article

Sustainability involves continuously enhancing processes to yield long-term environmental, economic, and social benefits. The construction industry necessitates innovative and practical approaches in both education and construction practice to foster sustainable development. This study contributes to the discourse on sustainability in engineering education and construction practice by presenting the outcomes of the European-funded project “CLOEMC VI—Common Learning Outcomes for European Managers in Construction”. The main aim of this study is to investigate construction practices and civil engineering education from the perspective of sustainability considering the impact of earthquakes on the construction sector. This study incorporates insights from interviews conducted with construction professionals in the region affected by the February 2023 Kahramanmaras earthquakes in Turkey. The interviews examine reflections on building sustainable cities through earthquake-resilient practices. This study also conducts a questionnaire survey targeting academics in civil engineering departments in Turkey. The questionnaire survey evaluated the integration of sustainability and resilience into civil engineering curricula. The key contribution of this research lies in demonstrating how the manuals developed under the EU-funded project can be effectively integrated into engineering education and how insights from disaster-affected communities can inform a more robust framework for sustainability. This study provides valuable guidance for policymakers and researchers in developing strategies for implementing sustainability in engineering education and the construction industry, ultimately contributing to the advancement of sustainable development practices. Full article