Van Earthquake Research Articles

Van Earthquake’s Effects on Mud-Brick Houses in Van and the Last Survived Buildings

Van Earthquake’s Effects on Mud-Brick Houses in Van and the Last Survived Buildings

Seismic Assessment of Masonry Minarets under Different Earthquakes

Minarets are tall and slender structures and form important elements of mosques. Most historical minarets are constructed with masonry (brick or stone units), while modern minarets typically use reinforced concrete. Recent earthquakes have shown that the majority of these structures are highly susceptible to seismic excitation leading to a range of structural damage, from minor cracking to complete collapse. In this paper, the seismic response of a representative masonry minaret was investigated using acceleration records of the 1999 Kocaeli, 2003 Bingöl and 2011 Van earthquakes. All acceleration records were scaled according to the location of the minaret. For this purpose, a representative masonry minaret that is thought to have been built in the city's central part of Elazığ, Turkey was chosen. After the seismic analysis, displacement and stress values obtained on the minaret were presented. It was seen that the displacements were increased along the height of the minaret. Also, the maximum and minimum stress values were obtained between the cylindrical body and transition segment of the minaret in accordance with the damage zones in the past earthquakes.

Seismo-ionospheric precursory detection using hybrid Bayesian-LSTM network model with uncertainty-boundaries and anomaly-intensity

Several efforts have been made to understand the complex physical processes involved in a seismic process, but the findings are vague considering prediction capabilities. Nevertheless, recent seismo-ionosphere precursory research has enlightened new pathways toward building an earthquake (EQ) forecasting system. Previously, some conventional mathematical/statistical approaches have been proposed for detecting an anomalous value as a potential precursor. We propose a hybrid Bayesian-based Long Short-Term Memory (B-LSTM) Network model to forecast the Total Electron Content (TEC) data. We applied B-LSTM on different Vertical TEC (VTEC) datasets of two EQs (Mw7.7 Awaran EQ and Mw7.1 Van EQ) by forecasting VTECs with Normalised Root Mean Square Error (NRMSE) scores of 0.15 and 0.10, respectively. We calculated errors and estimated the 99 % confidence interval to extract the VTEC anomalies. The model detects VTEC anomalies successfully but these anomalies may still have some biases and may lead to a false alarm. In order to minimize possible false alarms, we calculated the intensity of each anomaly and found a strong anomaly that occurred 2–3 days before the EQs. To strengthen the relationship of the detected VTEC anomalies with the investigated earthquakes, we examined the state of space weather conditions during and before the event. Our analysis expands the use of deep learning methods in EQ prediction and VTEC forecasting that can be used for various applications e.g. space weather and navigation.

Evaluation of Post-Earthquake Late-Term Trauma Levels in Dialysis Patients and Healthcare Professionals

Objective: To determine and compare the post-earthquake trauma levels of hemodialysis (HD) patients, healthcare professionals working in the HD unit, and peritoneal dialysis (PD) patients in the 11th month of two earthquakes that occurred approximately nine hours apart on February 6, 2023, and affected the east and southeast regions of Turkey. Materials and Methods: The study included a total of 162 individuals, including 87 HD and 35 PD patients who had experienced both earthquakes, and 40 healthcare professionals working in the HD unit. The post-earthquake trauma levels of the participants were assessed using the Scale That Determines the Level of the Trauma After the Earthquake (SDLTAE), consisting of a total of 20 items, developed by Tanhan et al. after the 2011 Van earthquake. The individuals with an SDLTAE score of >52 were considered highly traumatized. Results: The mean age of the participants was 53±16 years, and 79 (49%) were women. The SDLTAE score of the HD patients was found to be higher than that of the PD patients (p=0.006). There were no significant differences between the SDLTAE scores of the healthcare professionals and the HD and PD patients (p=0.419 and p=0.089, respectively). Upon comparing patients with low and high total SDLTAE scores, we observed that the rate of female individuals was higher in all groups (p<0.001 for the HD and PD groups; p=0.017 for healthcare professionals). No correlation was found between the total SDLTAE score and age, dialysis duration, or laboratory parameters among the HD and PD patients (p>0.05). Conclusion: We found that HD patients had a higher level of trauma than PD patients. Our study showed that women were more traumatized than men in sensitive groups, such as those receiving dialysis and healthcare professionals. Regularly conducting psychological assessments for dialysis patients and healthcare professionals may increase the likelihood of early intervention.

Precarity and patriarchal bargain: women’s experiences in post-disaster recovery housing after the 2011 Van earthquake

In this paper, we frame women’s experiences in post-disaster recovery housing to highlight the differential distribution of their vulnerabilities. While studies have reported women’s resilience in their new residence, their social vulnerability is often exacerbated in post-disaster recovery housing as they disproportionately shoulder the familial responsibilities with limited resources. We collected and analyzed 350 face-to-face interviews with women survivors living in the post-disaster recovery housing after the 2011 Van earthquake. Using Butler’s concept of precarity, we argue that under the prevailing patriarchal system, the physical location and the configuration of the new residence, and women’s familial status continue to differentially pose challenges for displaced women and worsen their vulnerabilities even years after their relocation. We found that while some women experienced positive changes, they continue to bargain with patriarchy, underlining the oppressiveness of the patriarchal system

Disaster Challenges for Individuals with Special Needs and Their Parents: The Case of the 2011 Van Earthquake

Afetler toplumsal normların askıya alındığı, gündelik yaşamın derinden yarıldığı zor süreçlerdir. Özellikle depremler çok daha sarsıcı olup, kısa süre zarfında toplumsal sistemi işleyemez hale getirebilmektedir. Bu süreçte afetzedelerin yaralanmadan tahliye olmaları, acil toplanma alanlarına geçmeleri ve evlerinden uzakta, sınırlı koşullar içerisinde yaşama tutunmaları gerekir. Toplumun her kesimini zorlayan afet dönemleri özellikle özel gereksinime ihtiyaç duyan engelli bireyleri ve onların ailelerini çok daha derinden etkilemektedir. Kendi ihtiyaçlarını gideremeyecek düzeyde bir engele sahip bireyler ve onlardan sorumlu ebeveynler için bu dönemler çok daha kırılgan olmaktadır. Bu araştırma tam da böyle bir süreci ortaya çıkarmak için yapılmıştır. Zihinsel yetersizliği nedeniyle özel gereksinim ihtiyacı duyan engelli bireylerden sorumlu ebeveynlerin, acil akut süreçlerinde yaşadıkları zorluklar ortaya çıkarılmaya çalışılmıştır. Araştırma, 2011 Van Depremlerine maruz kalmış özel gereksinimli çocuklara sahip 10 anneyle yarı yapılandırılmış görüşmeye dayanmaktadır. Tespitler bu ailelerin dezavantajlı durumlarının kurbanı olduklarını ortaya koymaktadır. Tahliye sürecinde önemli zorluklar ile karşılaşan aileler, temel ihtiyaçlarını uzun süre karşılayamadılar. Ekonomik yetersizlikleri nedeniyle kırılganlıklarının çok daha arttığı tespit edilen bu aileler, birçok konuda kendilerini çaresiz hissetmişlerdir. Tahliye, barınma, temel ihtiyaçların giderilmesi konusunda yeterince destek alamadıklarını belirten aileler, kamu hizmetlerine erişimde sıkıntılar yaşamışlardır. Acil akut sürecindeki barınma koşullarının (konteyner kentler) özel gereksinimli bireylere uygun olmadığını belirten aileler, bu süreçte yaşadıkları zorlukların katlanarak arttığını belirtmişlerdir.

Determination of Natural Fundamental Period of Minarets by Using Artificial Neural Network and Assess the Impact of Different Materials on Their Seismic Vulnerability

Minarets are slender and tall structures that are built from different types of materials. Modern materials are also starting to be used in such structures with the recent developments in material technology. The seismic vulnerability and dynamic behavior of minarets can vary, depending on the material characteristics. Within this study’s scope, thirteen different material types used in minarets in Türkiye were chosen as variables. A sample minaret model was chosen as an example with nine different heights to reveal how material characteristic change affects seismic and dynamic behavior. Information and mechanical characteristics were given for all the material types. Natural fundamental periods, displacements, and base shear forces were attained from structural analyses for each selected material. The empirical period formula for each material is proposed using the obtained periods, depending on the different minaret heights taken into consideration. At the same time, fundamental natural periods for the first ten modes and 13 different types of materials used in the study were estimated with the established Artificial Neural Network (ANN) model. The real periods from the experimental analyses were compared with the values estimated by the ANN using fewer parameters, and 99% of the results were successful. In addition, time history analyses were used to evaluate the seismic performance of the minaret (three different materials were considered). In this specific case, the acceleration record from the 2011 Van (Eastern Turkiye) earthquake (Mw = 7.2) was taken into consideration. Performance levels were determined for the minaret according to the results obtained for each material. It has been concluded that material characteristics significantly affect the dynamic and seismic behavior of the minarets.

Dynamic Analysis of Historical Masonry Arch Bridges under Different Earthquakes: The Case of Murat Bey Bridge

Historical structures, which constitute an important part of our cultural heritage, should be well protected and carried into the future. Masonry arch bridges are significant part of these structures. In this study, the single-span Murat Bey Bridge in the province of Kütahya, built in 1460, was studied as a numerical application. Firstly, three dimensional finite element model of the bridge was constituted with SAP2000 finite element program. Static analysis of the bridge under its own weight was carried out. The modal analysis method was used to obtain the dynamic characteristics of the bridge. Then, time-history analysis method was applied for seismic evaluation of the bridge. For this purpose, the acceleration records of the 1998 Adana, 2003 Bingöl, 2011 Van and 2020 Elazığ earthquakes were taken into consideration. As a result of the dynamic analyses carried out, the displacement and stress graphs occurring on the bridge were examined. The highest displacement and stress values on the historical bridge were obtained from the acceleration records of the 2011 Van earthquake.

Architectural Characteristics and Seismic Vulnerability Assessment of a Historical Masonry Minaret under Different Seismic Risks and Probabilities of Exceedance

Masonry structures began to be built with the existence of human beings and are an inspiration for today’s structures. Monumental historical buildings built according to people’s religious beliefs have special importance among such structures. Despite being exposed to many natural disasters over time, such structures that have survived till today are an indispensable part of the historical heritage. Within the scope of this study, structural analyses were carried out for the historical Ulu Mosque’s minaret in Bitlis (Turkey), located in the Van Lake basin, using both on-site measurements and finite element methods. Detailed historical and architectural features were given for the minaret and the mosque. In addition to four different earthquake ground motion levels of 2%, 10%, 50% and 68%, structural analyses were deployed separately for seven different geographical locations in the same seismic risk area. Moreover, time history analyses were conducted using the acceleration records of the Van earthquake that occurred in the region. The minaret performance levels were determined by using the displacement values obtained. The study examined the different probabilities of exceedance and the changes in the regions with the same seismic risk. As a result of each structural analysis, base shear forces, displacement, period and maximum stress values were obtained for the minaret. The displacement, base shear force, and stress values increased as the exceedance probability decreased. While the same seismic and structural analysis results were obtained for the selected settlements in the same earthquake zone in this study, remarkable differences were observed for these settlements using the geographical-location-specific design spectrum.

Residents’ satisfaction in post-disaster permanent housing: Beneficiaries vs. non-beneficiaries

This paper examines the satisfaction of residents living in post-disaster permanent housing, with particular emphasis on the pre-disaster neighborhood experiences and beneficiary status. Data were obtained by a face-to-face questionnaire survey (N = 171) conducted between January 15 and May 25, 2014, in Sihke post-disaster permanent housing, which was built after the 2011 Van earthquakes in Turkey. Pearson's correlation analysis was used to measure the effect of the relationships between the variables used in the regression analysis. An independent sample t-test was used to assess residents' evaluations of the physical and social settings in the pre-disaster and present resettlement areas, based on their ownership status (beneficiaries versus non-beneficiaries). Hierarchical multiple regression analysis was used to determine which factors influenced overall satisfaction with the neighborhood, with beneficiary status, past residential experiences, the social environment, and socio-demographic factors as controlling variables. The preliminary findings show that being a beneficiary, the pre-disaster and current neighborhood environments, and social ties are dimensions and predictors of residents' satisfaction with post-disaster permanent housing in the context of Van, Turkey.

Post-Earthquake Damage Assessments of Historic Mosques and Effects of Near-Fault and Far-Fault Ground Motions on Seismic Responses

ABSTRACT This paper is based on the the post-earthquake evaluation of two heavily damaged historic masonry mosques and the investigation of the effects of near-fault and far-fault ground motions on their seismic behaviors. The Hüsrev Pasha and Kaya Çelebi mosques, located in Van province, Turkey, were exposed to two devastating earthquakes (on October 23, 2011 and November 9, 2011) and their aftershocks. The minaret, the dome covering the main structure and porch of Kaya Çelebi mosque and the porch of Hüsrev Pasha mosque collapsed after earthquakes. This paper consists of two main sections. In the first, the post-earthquake performances of the mosques, and the damage to them, is evaluated by using the linear time-history analyses. In the other, the structural responses of the mosques are compared in order to evaluate the near-fault and far-fault ground motion effects on seismic behaviors. Results indicate that the vertical components of the 2011 Van earthquakes lead to structural responses for the mosques which are as crucial as their horizontal components. This is due to the vibration modes in the vertical direction, with and without high modal participating mass ratios, corresponding to high spectral acceleration values. It has been found that this situation significantly affects the structural behavior of mosques and especially domes. However, the analyses show that both near-fault and far-fault ground motions may have substantial effects on such historic structures, depending on the earthquake characteristics.

Evaluation of field visit planning heuristics during rapid needs assessment in an uncertain post-disaster environment

A Rapid Needs Assessment process is carried out immediately after the onset of a disaster to investigate the disaster’s impact on affected communities, usually through field visits. Reviewing practical humanitarian guidelines reveals that there is a great need for decision support for field visit planning in order to utilize resources more efficiently at the time of great need. Furthermore, in practice, there is a tendency to use simple methods, rather than advanced solution methodologies and software; this is due to the lack of available computational tools and resources on the ground, lack of experienced technical staff, and also the chaotic nature of the post-disaster environment. We present simple heuristic algorithms inspired by the general procedure explained in practical humanitarian guidelines for site selection and routing decisions of the assessment teams while planning and executing the field visits. By simple, we mean methods that can be implemented by practitioners in the field using primary resources such as a paper map of the area and accessible software (e.g., Microsoft Excel). We test the performance of proposed heuristic algorithms, within a simulation environment , which enables us to incorporate various uncertain aspects of the post-disaster environment in the field, ranging from travel time and community assessment time to accessibility of sites and availability of community groups. We assess the performance of proposed heuristics based on real-world data from the 2011 Van earthquake in Turkey. Our results show that selecting sites based on an approximate knowledge of community groups’ existence leads to significantly better results than selecting sites randomly. In addition, updating initial routes while receiving more information also positively affects the performance of the field visit plan and leads to higher coverage of community groups than an alternative strategy where inaccessible sites and unavailable community groups are simply skipped and the initial plan is followed. Uncertainties in travel time and community assessment time adversely affect the community group coverage. In general, the performance of more sophisticated methods requiring more information deteriorates more than the performance of simple methods when the level of uncertainty increases.

An integrated critical approach to off-fault strike-slip motion triggered by the 2011 Van mainshock (Mw 7.1), Eastern Anatolia (Turkey): New stress field constraints on subcrustal deformation

In this study, we retrieved the finite source characteristics of the October 23, 2011 Van earthquake (Mw 7.1) using the teleseismic waveforms to focus on the source location. The outstanding off-fault aftershock sequence of the Van mainshock was readily explained by calculating the Coulomb stress changes imparted to the surrounding crust. This may be accomplished through finite source modelling to examine the stress interaction between the fault, ruptured by the Van mainshock, and the surrounding fault(s) triggered by the same mainshock. In addition, to provide further support for the Coulomb failure stress changes in the off-fault area, centroid moment tensor (CMT) inversion of the off-fault aftershocks was performed and stress tensors were derived from their focal solutions. This identified the dominant fault slip, the constraints of the crustal stress fields and illuminated the crustal nature of the stress interaction. The off-fault aftershocks showed a strike-slip stress regime in rotational (to NW) and non-rotational (to N) stress fields of the upper and lower crusts, respectively. However, this was inconsistent with a horizontal compressional stress direction striking to the north. This suggests that a local source and/or rotation of lateral variation in stress magnitudes in crustal and sub-crustal structures strongly perturbed the regional stress field. It was also evident that these strike-slip aftershocks increased the intensity of stress in an off-fault area, NE of the source rupture. This revealed a uniquely triggered strike-slip motion, activated and rooted in the weak lower crust. We conclude that the Van mainshock rupture source area, associated with the stress changes imparted to the surrounding crust, had undergone anomalous modifications to generate distinctive off-fault aftershock responses in the entire crust, and also triggered and loaded the weak lower crust. We hypothesize that the strike-slip motion, the so called “transfer fault”, as a distinctly triggered slip event, was generated or selectively activated by subcrustal ductile processes in the absence of mantle lid beneath the study area. However, local slab fragmentation, tearing and cold mantle beneath the study area lead to paradigm changes in interpreting the strike-slip motion and subcrustal deformation. The presence of a small piece of oceanic lithosphere, consistent with fragmented, torn slab and cold mantle, may be an alternative hypothesis that remains to be tested. The Van earthquake, combined with careful examination of associated off-fault aftershocks, revealed new information about stress field constraints on subcrustal deformation. This investigation also provided insights into an important role of stress interaction, with a newly discovered transfer fault within the off-fault area, which extends through the entire crust beneath Lakes Van and Erçek areas.

Determination of Stress and Deformation Zones of Historical Mus Murat Bridge

This study was carried out to determine the strength of long span stone bridges and stress areas of a historical bridge by using finite element method during earthquakes, floods, and vehicle traffic. The possible earthquake impact of the region and the behavior of the bridge under the effect of the 2011 Van earthquake were investigated. The stresses that will be caused by hydrostatic and vehicle loading applied to the bridge are dwelled on. This study aimed to shed light on future restoration work. As a result of the vehicle, hydrostatic load and dead load analysis, the biggest deformation occurred in the arch K9, which has the largest arch span. According to the results of the earthquake analysis, maximum deformation occurred in the K10 arch, which is one of the arches with the largest arch span of the bridge. In addition, inearthquakes affected in the X and Z direction, it was observed that the arches and piers in the middle of the bridge, that is, these relatively higher structural elements were subjected to more stress. It has been determined that the A11 pier of the bridge is the structural element exposed to the most pressure.

Successful Seismic Performance of Bridges after Sivrice Earthquake

Most bridges in Turkey were proven to have successful seismic performance during recent earthquakes such as the Van earthquake, Mw 7.1, in 2011 and the Sivrice earthquake, Mw 6.7, in 2020. All bridges close to the epicenter of the earthquakes were still in service immediately after the catastrophic events, even though some of them were located near the vicinity of the fault line. This paper reports the performance of inspected bridges in the Sivrice earthquake zone, including the soil stability around abutments, and investigated the seismic performance of an old composite steel bridge that survived the earthquake. Field trips were conducted to the area for the postinspection of selected bridges. The geometric design of the old steel bridge was identified through classical measurement tools and point cloud models obtained from digital drone pictures in the absence of original design documents. The modern structural analysis of the old lightweight steel bridge with real-time earthquake records indicated that the bridge remained in the elastic state due to its flexibility.

Crustal Movements and Deformations in Eastern Turkey in Connection with the Van Earthquake (October 23, 2011, Мw = 7.2): Study from GPS Data

Crustal Movements and Deformations in Eastern Turkey in Connection with the Van Earthquake (October 23, 2011, Мw = 7.2): Study from GPS Data

VAN GÖLÜ BÖLGESİNDE 2011 YILI DEPREMLERİNİN ARTÇI ŞOK SERİSİ KIRILMA KARMAŞIĞINA YAPISAL BAĞLANTI(DOĞU ANADOLU, TÜRKİYE)

This study presents an analysis of the structural coupling to the two large destructive earthquakes that occurred in Lake Van area on October 23 (Mw 7.1), and November 9 (Mw 5.6), 2011, together with the azimuth-dependent distribution of the seismic activity and microseismicity clusters after the mainshocks, associated with the complex rupture processes of the aftershock sequence. The aftershock sequences after the two mainshocks were linked to the local crustal faults beneath Lake Van area, followed successively and produced unusually intense activity and significant damage in the area. The main purposes of this study are to document the spatial and temporal distribution and evolution of the October 23, 2011 aftershock hypocenters and the azimuth-dependent distribution of seismic activity, and to understand the structural character of the aftershock sequence using the distributional and evolutional patterns of the aftershock hypocenters. A total of 10,000 aftershocks were obtained from seismic data with a high signal-to-noise ratio collected over three years from October 23, 2011 to March 17, 2014. These aftershocks were relocated for the time periods from November 2011 through March 2012 to March 2014 and ≈ 5000 aftershocks were retained in the depth versus distance cross-sections to detect the clusters in the first step of study (November 2011-March 2012). The focal depth distribution of the aftershock clusters, the migration of hypocenter activity and microseismicity clusters were analyzed and the distributional patterns of the detected clusters were assessed using the geometric distribution of the aftershock hypocenters. The spatial and temporal distribution of aftershocks reveals interesting key features of the deep rupture complexity of the Van earthquake. This study presents the results of the first detailed hypocentral observations and this is important data for future seismic hazard analyses in the study area.

Seismicity of East Anatolian of Turkey and Failures of Infill Walls Induced by Major Earthquakes

There are three major fault zones in Turkey scattered around the country known as East Anatolian Fault (EAF), North Anatolian Fault (NAF) and Anatolian-Aegean Subduction Zone (AASZ). Last two decades, EAF has been rather quiescent compared with NAF. However, this quiescence was broken in the beginning of the millennium. The strong shaking was started in 2003 with Bingöl earthquake (Mw = 6.3) and the last earthquake on the EAF is the Sivrice-Elazığ (Mw = 6.8) on January 24, 2020. Strong seismicity of these faults damaged the structures severely and caused death of the habitants. This study aims to present, seismotectonic of the region, general characteristics of the earthquakes and more specifically to report structural damage of infill walls of the structure’s damages caused by these earthquakes. Damage evaluation and identification of the observed infill wall damages due to 2003 Bingöl, 2011 Van earthquakes and January 24, 2020 Sivrice-Elazığ earthquake occurred Turkey’s Eastern region, were presented, and possible solutions were suggested. Moreover, the effects of the infill walls on the behavior of structures under static and dynamic load cases are discussed that experienced in these earthquakes. Damages are classified according to formations such as in-plane or out-of-plane, evaluations and the results obtained from the discussions are presented for each category.

Prolonged grief disorder among bereaved survivors after the 2011 Van Earthquake in Turkey

The aim of the current study was to investigate the ratio and predictors of probable Prolonged Grief Disorder (PGD) among bereaved survivors eight years after the 2011 Van earthquake. Among a sample of 495 survivors who experienced loss as a result of this earthquake, 8.9% met the criteria of probable PGD. In the binary logistic regression analysis, being woman, being aged 40 or over, personal injury, property damage, losing family members, and the psychological impact of the earthquake predicted probable PGD. The current study highlights the importance of considering PGD among bereaved survivors after earthquakes.

The importance of effective land use planning for reduction in earthquake catastrophe

Over 60% of the countries just like Turkey have suffered from earthquakes. The observations have revealed that the buildings/civil engineering structures in/on the rocky grounds did not get damaged by the earthquakes. The major reason behind it is that the modulus of elasticity of saturated rocks is million times greater than that of saturated soil units. Furthermore, while the saturated soil units are susceptible to liquefaction (shear strength approaches to zero) at varying degrees, rock units do not get liquefied. None of the structures on the rocky ground has been affected by the recent destructive earthquakes studied by the authors and/or their colleagues in Turkey and abroad. As also has been highlighted by Marmara (17 August 1999) and Van (23 October 2011) earthquakes, the civil engineering structures in/on rocky grounds, even adjacent to the epicenter, have not been affected by the destructive earthquakes in respective regions that are seismically active. It is quite explicit that the number of casualties in the settlements in/on rocky grounds is zero. In Turkey, the land required for housing is 1% of the country. However, 57% of the area is available for construction. The remaining 43% consists of forest, restricted zones, and the lands of fertile soil which are composed of soil plains and landslides. Thus, the earthquake disasters can be overwhelmed by effective land use planning.