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1.
Consecutive earthquakes occurred on October 23rd, 2011 in Ercis and on November 9th, 2011 in Edremit that are townships located 90 km and 18 km far from Van city in Turkey, respectively. A total of 28,000 buildings were damaged or collapsed in the city center and the surrounding villages after the Ercis earthquake. This number reached 35,000 after the Edremit earthquake. In the area where the earthquakes occurred, almost all the reinforced concrete buildings were affected.This study presents field observations of damages on reinforced concrete buildings due to the consecutive earthquakes that occurred in Van, Turkey. Damages appearing in the buildings may occur due to several reasons such as site effect, poor construction quality, poor concrete strength, poor detailing in beam-column joints, detailing of stronger beam than column, soft stories, weak stories, inadequate reinforcement, short lap splices, incorrect end hook angle, and short columns. Aftershocks also caused progressive damages on the buildings within 17 days after the earthquakes. According to the results of this study, most of the damaged buildings were not designed and constructed according to the Turkish earthquake code, the so-called Specification for Buildings to be built in Seismic Zones. 相似文献
2.
Although the M
w
= 6.1 Kovancilar-Turkey earthquake of March 8, 2010 had a moderate intensity with a recorded PGA of 0.07g, it caused heavy damages in 2870 residential buildings having traditional or masonry structural systems and 42 human loss.
Damage has been reported to be particularly concentrated at Kovancilar and Palu counties of Elazig province. Five hours after
this earthquake, an aftershock of M
L
= 5.6 with a PGA of 0.08g struck the same region, developing the existing damages in the structures. In order to investigate this significant amount
of reported damages under the effect of such low ground shakings, our reconnaissance team arrived at the region and unexpectedly
came across a two-story RC building settled on a slope in Yukari Demirci village, which suffered moderate damage during the
shakes. The outline of this paper can be summarized as the presentation of the results of the investigations in the order
of describing the overall observed damages within the region; evaluation of the recorded motions; the details of the field-work
carried out for the two story RC building and the analytical estimation of the site-assessed damages by means of nonlinear
dynamic analysis. Employing the gathered data, the building is analytically modeled as plane frames and analyses are performed
under the effects of the processed earthquake records, which are applied to the structure one after another in the consistent
directions due to the building location. It is shown herein that the structural elements remain in the elastic range subjected
to the processed recorded motions; henceforth acceleration time histories are scaled step by step up to 0.40g and computations are repeated for each acceleration level. Comparison with the observed and the analytically obtained damages
confirmed that approximately 0.30g of peak ground acceleration should have to be exposed during the earthquakes. 相似文献
3.
In May 2008 a shallow Mw6.3 earthquake struck South Iceland with an epicentre close to two small towns. Nearly 5000 low-rise residential buildings were affected. The recorded maximum PGA was 0.88 g. A great deal of damage occurred, but there was no loss of life. In Iceland all buildings are registered in a detailed official database and insurance against natural disasters is obligatory. As the repair costs for every affected building had to be assessed for insurance purposes this provided an unusual opportunity to review structural performance across the whole population of buildings in the affected area. The estimated repair cost was classified in a number of subcategories covering structural and non-structural damage for five different residential building typologies. Study of these buildings showed that non-structural damage dominated the overall damage. The main monetary damage was cosmetic damage of partition walls and flooring. The structural systems performed quite well and no buildings collapsed. 相似文献
4.
5.
LIU Jun SHUAI Xianghu HONG Zhonghu TAN Ming ZHAO Shuo YAO Yuan ZHANG Meng LI Shijie 《中国地震研究》2020,34(2):296-306
In this paper, the tilt photography data acquisition and three-dimensional modeling of the Tashkurgan MS5.5 earthquake in Xinjiang are conducted using the tilt photography system of the Rotor UAV. The three-dimensional model is used to interpret the earthquake damage on buildings in the mega-earthquake area in order to acquire different-level house damage in the Kuzirun village disaster area. In addition, the characteristics of seismic damage on typical buildings are analyzed. The results show that the main collapsed houses in the mega-earthquake area are sand-stone buildings, of which about 39% are sand-stone buildings. Several brick-wood buildings and brick-concrete buildings are seriously damaged, while the buildings with frame structures are mainly slightly damaged, and the houses near the macro-epicenter of the earthquake are all in good conditions. Three-dimensional tilt photography technology can vividly display the scene of earthquake disaster, and can provide significant demonstration in building damage degree together with detailed analysis of disaster situation. 相似文献
6.
On February 27, 2010 an earthquake of magnitude Mw=8.8, with epicenter in Cobquecura, Maule region, hit the central part of Chile. After the earthquake, a tsunami occurred that caused heavy casualties and damage to buildings and infrastructure. In particular, 4.5% of the overpasses located in the affected region suffered some type of damage and 25 bridges and several pedestrian bridges collapsed. At that time, there were about a dozen bridges with seismic isolation bearings in Chile, two of which were instrumented with accelerometer networks: the Marga Marga Bridge, located in Viña del Mar, and an elevated section of the Metro Line 5 in Santiago, at approximately 300 km and 400 km from the epicenter, respectively. This paper analyzes the acceleration records obtained at these instrumented structures and studies the effect of the seismic isolation on their dynamic response. The beneficial effect of the isolation system, especially in the longitudinal direction, is apparent. In addition, some flaws in the collapsed bridges are described. 相似文献
7.
M. D. Trifunac S. S. Ivanov M. I. Todorovska E. I. Novikova A. A. Gladkov 《Soil Dynamics and Earthquake Engineering》1999,18(3):375
This article explores the possibility to measure deformations of building foundations from measurements of ambient noise and strong motion recordings. The case under study is a seven-storey hotel building in Van Nuys, California. It has been instrumented by strong motion accelerographs, and has recorded several earthquakes, including the 1971 San Fernando (ML=6.6, R=22 km), 1987 Whittier–Narrows (ML=5.9, R=41 km), 1992 Landers (ML=7.5, R=186 km), 1992 Big Bear (ML=6.5, R=149 km), and 1994 Northridge (ML=6.4, R=1.5 km) earthquake and its aftershocks (20 March: ML=5.2, R=1.2 km; 6 December, 1994: ML=4.3, R=11 km). It suffered minor structural damage in 1971 earthquake and extensive damage in 1994. Two detailed ambient vibration tests were performed following the Northridge earthquake, one before and the other one after the 20 March aftershock. These included measurements at a grid of points on the ground floor and in the parking lot surrounding the building, presented and analyzed in this article. The analysis shows that the foundation system, consisting of grade beams on friction piles, does not act as a “rigid body” but deforms during the passage of microtremor and therefore earthquake waves. For this geometrically and by design essentially symmetric building, the center of stiffness of the foundation system appears to have large eccentricity (this is seen both from the microtremor measurements and from the earthquake recordings). This eccentricity may have contributed to strong coupling of transverse and torsional responses, and to larger than expected torsional response, contributing to damage during the 1994 Northridge, earthquake. 相似文献
8.
Yanbo Zhang Yueren Xu Wenqiao Li Runchao Liu Ruoyu Mu Jiayi Li Da Zhang Haofeng Li Qinjian Tian 《地震研究进展（英文）》2022,2(2):100133
At 02:04 on May 22, 2021, an MS 7.4 earthquake occurred in Madoi County in Qinghai Province, China. This earthquake is the largest seismic event in China since the 2008 MS 8.0 Wenchuan earthquake. Thus, it is critical to investigate surface deformation and damage in time to accurately understand the seismogenic structure of the Madoi earthquake and the seismogenic capacity of the blocks in this region. This study focuses on the Xuema Village, located at the eastern end of the coseismic surface ruptures produced by the event, and assesses the deformation and seismic damage in this area based on field surveys, UAV photogrammetry, and ground penetrating radar (GPR). The results indicate that the rupture scale is substantially smaller at the eastern end of the rupture zone compared to other segments. En echelon type shear tensile fractures are concentrated in a width range of 50–100 m, and the width of single fractures ranges from 20 to 30 cm. In contrast, the degree of seismic damage significantly increases at this site. All of the brick and timber houses are damaged or collapsed, while the steel frame structures and the color steel houses are slightly damaged. More than 80% of the bridge decks on the Changma River Bridge collapse, similar to the terraces along the Youerqu and Changma Rivers and the cut slopes of Provincial Highway S205. We infer that the seismogenic fault of the Madoi earthquake exerts a tail effect in this segment. The tension zone has led to a reduction at the eastern end of the rupture zone, causing shaking damage. Local topography and buildings without earthquake-resistant construction along the strike of the rupture zone have undergone different levels of seismic damage. 相似文献
9.
Earthquakes have a greater effect on society than most people think. These effects range from structural damages to economic impacts and fatalities. An earthquake only lasts for a few seconds and the aftershocks may continue for days, but the damage does continue for years. Residential site safety and earthquake damage assessment studies play a crucial role in developing reliable rehabilitation and development programs, improving preparedness and mitigating losses in urbanized areas. The extremely densely populated metropolis of Tehran, which totals of 7,768,561 for 22 districts (according to the 2006 population census), coupled with the fragility of houses and infrastructure, highlight the necessity of a reliable earthquake damage assessment based on essential datasets, such as building resistance attributes, building population, soil structures, streets network and hazardous facilities. This paper presents a GIS-based model for earthquake loss estimation for a district in Tehran, Iran. Damages to buildings were calculated only for the ground shaking effect of one of the region's most active faults, the Mosha Fault in a likely earthquake scenario. Earthquake intensity for each building location was estimated based on attenuation relation and the ratio of damage was obtained from customized fragility curves. Human casualties and street blockages caused by collapsed buildings were taken into account in this study, as well. Finally, accessibility verification found locations without clear passages for temporary settlements by buildings via open streets. The model was validated using the 2003 Bam earthquake damages. The proposed model enables the decision-makers to make more reliable decisions based on various spatial datasets before and after an earthquake occurs. The results of the earthquake application showed total losses as follows: structural damages reaching 64% of the building stock, a death rate of 33% of all the residents, a severe injury rate reaching 27% of the population and street closures upwards of 22% due to building collapse. 相似文献
10.
Ahmed Mebarki Mehdi Boukri Abderrahmane Laribi Mohammed Farsi Mohamed Belazougui Fattoum Kharchi 《Journal of Seismology》2014,18(2):331-343
When dealing with structural damages, under the effect of natural hazards such as earthquakes, it is still a scientific challenge to predict the potential damages, before occurrence of a given hazard, as well as to evaluate the damages once the earthquake has occurred. In the present study, two distinct methods addressing these topics are developed. Thousands (～54,000) of existing buildings damaged during the Boumerdes earthquake that occurred in Algeria (Mw?=?6.8, May 21, 2003) are considered in order to study their accuracy and sensitivity. Once an earthquake has occurred, quick evaluations of the damages are required in order to distinguish which structures should be demolished or evacuated immediately from those which can be kept in service without evacuation of its inhabitants. For this purpose, visual inspections are performed by trained and qualified engineers. For the case of Algeria, an evaluation form has been developed and is still in use since the early 80s: Five categories of damages are considered (no damage or very slight, slight, moderate, major, and very severe/collapse). This paper develops a theoretical methodology that processes the observed damages caused to the structural and nonstructural components (foundations, roofs, slabs, walls, beams, columns, fillings, partition walls, stairways, balconies, etc.), in order to help the evaluator to derive the global damage evaluation. This theoretical methodology transforms the damage category into a corresponding “residual” risk of failure ranging from zero (no damage) to one (complete damage). The global failure risk, in fact its corresponding damage category, is then derived according to given combinations of probabilistic events in order to express the influence of any component on the global damage and behavior. The method is calibrated on a set of ～54,000 buildings inspected after Boumerdes earthquake. Almost 80 % of accordance (same damage category) is obtained, when comparing the theoretical results to the observed damages. For pre-earthquake analysis, the methodology widely used around the world relies on the prior calibration of the seismic response of the structures under given expected scenarios. As the structural response is governed by the constitutive materials and structural typology as well as the seismic input and soil conditions, the damage prediction depends intimately on the accuracy of the so-called fragility curve and response spectrum established for each type of structure (RC framed structures, confined or unconfined masonry, etc.) and soil (hard rock, soft soil, etc.). In the present study, the adaptation to Algerian buildings concerns the specific soil conditions as well as the structural dynamic response. The theoretical prediction of the expected damages is helpful for the calibration of the methodology. Thousands (～3,700) of real structures and the damages caused by the earthquake (Algeria, Boumerdes: Mw?=?6.8, May 21, 2003) are considered for the a posteriori calibration and validation process. The theoretical predictions show the importance of the elastic response spectrum, the local soil conditions, and the structural typology. Although the observed and predicted categories of damage are close, it appears that the existing form used for the visual damage inspection would still require further improvements, in order to allow easy evaluation and identification of the damage level. These methods coupled to databases, and GIS tools could be helpful for the local and technical authorities during the post-earthquake evaluation process: real time information on the damage extent at urban or regional scales as well as the extent of losses and the required resources for reconstruction, evacuation, strengthening, etc. 相似文献
11.
Vladimir G. Kossobokov 《Journal of Seismology》2018,22(5):1157-1169
We continue applying the general concept of seismic risk analysis in a number of seismic regions worldwide by constructing regional seismic hazard maps based on morphostructural analysis, pattern recognition, and the Unified Scaling Law for Earthquakes (USLE), which generalizes the Gutenberg-Richter relationship making use of naturally fractal distribution of earthquake sources of different size in a seismic region. The USLE stands for an empirical relationship log10N(M, L)?=?A?+?B·(5 – M)?+?C·log10L, where N(M, L) is the expected annual number of earthquakes of a certain magnitude M within a seismically prone area of linear dimension L. We use parameters A, B, and C of USLE to estimate, first, the expected maximum magnitude in a time interval at seismically prone nodes of the morphostructural scheme of the region under study, then map the corresponding expected ground shaking parameters (e.g., peak ground acceleration, PGA, or macro-seismic intensity). After a rigorous verification against the available seismic evidences in the past (usually, the observed instrumental PGA or the historically reported macro-seismic intensity), such a seismic hazard map is used to generate maps of specific earthquake risks for population, cities, and infrastructures (e.g., those based on census of population, buildings inventory). The methodology of seismic hazard and risk assessment is illustrated by application to the territory of Greater Caucasus and Crimea. 相似文献
12.
《地震研究进展（英文）》2023,3(1):100180
The report summarizes the observed damage to a variety of buildings near the epicenter of the M6.8 Luding earthquake in Sichuan Province, China. They include base-isolated buildings, multi-story reinforced concrete (RC) frame buildings, and masonry buildings. The near-field region is known to be tectonically highly active, and the local intensity level is the highest, that is, 0.4g peak ground acceleration (PGA) for the design basis earthquake, in the Chinese zonation of seismic ground motion parameters. The extent of damage ranged from the weak-story collapse that claimed lives to the extensive nonstructural damage that suspended occupancy. The report highlights the first observation of the destruction of rubber bearings and viscous dampers in the isolation layer of Chinese seismically isolated buildings. It also features the rare observation of the brittle shear failure of RC columns in moment-resisting frames in a region of such a high seismic design requirement. Possible reasons that may have attributed to the reported damage are suggested by providing facts observed in the field. However, careful forensic analyses are needed before any conclusive judgment can be made. 相似文献
13.
Murat Utkucu 《Journal of Seismology》2013,17(2):783-805
The 23 October 2011 Van earthquake took place in the NE part of Lake Van area, surprisingly on a fault (the Van fault) that is not present in the current active fault map of Turkey. However, occurrence of such a large magnitude earthquake in the area is not surprising regarding the historical seismicity of the region. The comparison of the damage patterns suggests that the earthquake is much likely a recurrence of the 1715 Van earthquake. The finite fault modelling of the earthquake using teleseismic broadband body waveforms has shown that the earthquake rupture was unilateral toward SW, was mostly reverse faulting, confined to below the depth of 5 km, did not propagate offshore, and was dominated by a failure of a single asperity with a peak slip of about 5.5 m. The total seismic moment calculated for the model is 4.6?×?1019 Nm (M W ?≈?7.1). The finite fault model coincides with the field observations indicating blind faulting and the vertical displacements over the free surface estimated from it correlate well with the maximum reported uplift along the coast of Lake Van above the hanging wall. The possible offshore continuations of the Van fault and some other faults lying its south are also discussed by assessing a previous offshore seismic reflection study and the earthquake epicentres and focal mechanisms. 相似文献
14.
Liquefaction which is one of the most destructive ground deformations occurs during an earthquake in saturated or partially saturated silty and sandy soils, which may cause serious damages such as settlement and tilting of structures due to shear strength loss of soils. Standard (SPT) and cone (CPT) penetration tests as well as the shear wave velocity (V s)-based methods are commonly used for the determination of liquefaction potential. In this research, it was aimed to compare the SPT and V s-based liquefaction analysis methods by generating different earthquake scenarios. Accordingly, the Erci? residential area, which was mostly affected by the 2011 Van earthquake (M w = 7.1), was chosen as the model site. Erci? (Van, Turkey) and its surroundings settle on an alluvial plain which consists of silty and sandy layers with shallow groundwater level. Moreover, Çald?ran, Erci?–Kocap?nar and Van Fault Zones are the major seismic sources of the region which have a significant potential of producing large magnitude earthquakes. After liquefaction assessments, the liquefaction potential in the western part of the region and in the coastal regions nearby the Lake Van is found to be higher than the other locations. Thus, it can be stated that the soil tightness and groundwater level dominantly control the liquefaction potential. In addition, the lateral spreading and sand boiling spots observed after the 23rd October 2011 Van earthquake overlap the scenario boundaries predicted in this study. Eventually, the use of V s-based liquefaction analysis in collaboration with the SPT results is quite advantageous to assess the rate of liquefaction in a specific area. 相似文献
15.
T. Rossetto N. Peiris J. E. Alarcon E. So S. Sargeant M. Free V. Sword-Daniels D. Del Re C. Libberton E. Verrucci P. Sammonds J. Faure Walker 《Bulletin of Earthquake Engineering》2011,9(1):11-37
On April 6, 2009 an earthquake of magnitude 6.2 (Mw) struck the Abbruzzo region of Italy causing widespread damage to buildings in the city of L??Aquila and surrounding areas. This paper summarizes field observations made by the Earthquake Engineering Field Investigation Team (EEFIT) after the event. The paper presents an overview of seismological and geotechnical aspects of the earthquake as well as a summary of the observed damage to buildings and infrastructure. A brief overview of the earthquake casualties is also reported. 相似文献
16.
In this study, seismic data recorded during the period 01/01/1996 to 09/01/2009 has been used to evaluate the seismic hazard potential along the Alborz region, Northern Iran. The technique of mapping local recurrence time, T L, is used to map major asperities, which are considered as the areas with maximum hazard. We calculated T L from a and b values which are in turn derived from the frequency–magnitude relation constants within a radius of 30 km about every corner point of a 10-km spacing grid. Since b value is inversely related to applied stress, the areas with lowest b values and/or shortest T L are interpreted to locate the asperities or the areas of maximum seismic hazard. To test this method, we computed T L map using seismic catalogues before and after the 2004 Baladeh earthquake of M w 6.2. The local recurrence time map before the earthquake shows anomalously short T L in the epicentral region of the Baladeh earthquake a decade before its occurrence. The T L map after the earthquake indicates that this large event has redistributed the applied stress in the Alborz region. The microseismicity of the region after the Baladeh earthquake, however, suggests that there are two anomalies in T L map positioned in Alborz. The places where these anomalies are observed can be considered as the areas with maximum seismic hazard for future large earthquake in the Alborz region. 相似文献
17.
The October 23, 2011 M7.2 Tabanli- Van and November 9, 2011 M5.2 Edremit – Van earthquakes caused damage in a widespread area across the Van province in Turkey. The ground motions, the damage caused by these earthquakes and the recent progress related to recovery efforts are presented herein. First, the key properties of the recorded strong ground motions like spectral amplitudes and directionality are evaluated. The observed damage in the affected reinforced concrete and masonry structures are discussed. The set of common structural damage mechanisms(i.e., soft story failure, torsional response due to plan irregularity, short column failure, pull out failure, pounding) observed in the damaged buildings were identified. The relationship between the key structural properties and the extent of damage is investigated. The primary loss drivers across the region were identified to be the poor quality of workmanship and improper use of building materials. The results from the investigation suggest that a large portion of the loss could have been prevented if sufficient attention and care were given to the implementation of the design regulations and in particular to the construction practice. Lastly, the recent progress in the ongoing rebuilding activities is presented. 相似文献
18.
利用2017年8月9日精河6.6级地震后获取的高分辨率无人机影像，对叶里斯南也肯村153栋房屋进行结构分类和震害解译，获取研究区内土木结构、砖木结构、砖混结构、框架结构4种类型房屋数量及震害特征，并依据解译结果计算每种结构房屋平均震害指数。由于研究区内砖木结构、砖混结构、框架结构房屋数量偏少，房屋内部的震害难以用无人机影像识别，这3类房屋的震害解译结果与现场调查结果相比差别较大，而土木结构房屋平均震害指数及所对应的地震烈度结果与现场调查结果基本一致，表明无人机影像可为房屋震害定量评估提供重要参考。 相似文献
19.
主要研究2009年7月24日西藏尼玛西南MS5.6地震的基本参数、地震序列特征、震源参数、发震构造等;利用震中附近600km范围内台站测定参数研究地震的震源机制解,与哈佛大学给出的震源机制解较一致,且与通过现场考察的发震断层走向具有一致性。研究认为本次地震发生在冈底斯山—拉萨块体内部,断裂为NNW向,主要受张应力作用产生左旋走滑正断层活动。此外还分析了震前地震学条带异常特征,结束表明,震前1年出现NW向条带非常显著,研究结论为该地区今后地震预测提供科学依据。 相似文献
20.
Paula Teves-Costa Carlos S. Oliveira M. Luisa Senos 《Soil Dynamics and Earthquake Engineering》2007,27(11):986-999
During the Mw=6.9 January 1, 1980 earthquake in the Azores, the damage distribution in the town of Angra do Heroísmo, in Terceira Island, had a non-homogeneous spatial character. In order to understand the observed pattern of damage a microtremor survey was carried out, using ambient vibrations, and the data were analysed with the J-Sesame software, following the H/V Nakamura methodology. The results are in good agreement with the surface geology and they show a good correlation with the observed damages. Two building surveys were performed, in 1980 on damage evaluation and in 2000 on characterization of few building parameters. With all these elements (surface geology type, soil peak frequency, building type, number of stories and damage level) for 2111 buildings it was possible to perform several interparameter analysis, which enabled the identification of indicators that could be used to improve the damage estimation for future events. 相似文献