Earthquake-hit Area Research Articles

Application of Mobile Signaling Data in Determining the Seismic Influence Field: A Case Study of the 2017 Mw 6.5 Jiuzhaigou Earthquake, China.

Seismic disasters are sudden and unpredictable, often causing massive damage, casualties and socioeconomic losses. Rapid and accurate determination of the scale and degree of destruction of the seismic influence field in an affected area can aid in timely emergency rescue work after an earthquake. In this study, the relationship between the changes in four types of mobile signaling data and the seismic influence field was explored in the 2017 Jiuzhaigou earthquake-hit area, China, by using the methods of comparative analysis, regression analysis and spatial autocorrelation analysis. The results revealed that after the earthquake, the number of mobile signaling significantly decreased. The higher the intensity, the more obvious the reduction of mobile signaling data and the later the recovery time. The Loginmac and WiFi data showed greater sensitivity than Gid and Station. There was a significant correlation between the changes in the mobile signaling numbers and the seismic intensity, which can more accurately reflect the approximate extent of the seismic influence field and the degree of actual damage. The changes in mobile signaling can provide a helpful reference for the rapid determination of seismic influence fields.

Damages and Failures of Structures in İzmir (Turkey) during the October 30, 2020 Aegean Sea Earthquake

ABSTRACT On 30.10.2020, a Mw = 6.6 magnitude earthquake occurred at the offshore Aegean Sea, hitting the western coast of Turkey and Samos Island of Greece, causing loss of lives and properties. In the scope of this study, a site investigation was conducted at the earthquake-hit area of İzmir (Turkey), where 17 buildings (7 partially, 10 totally) were collapsed and many of them were heavily damaged. The impact of the Aegean Sea Earthquake on structures in the İzmir region, as observed during this site investigation is presented in this paper. The seismic vulnerabilities of structures, by referring to the observed typical damages caused by the earthquake, are discussed and preliminary analyses were also conducted in two reinforced concrete buildings to investigate the causes of seismic damages. The damage mechanisms are explained to highlight the causes and defects that led to failure of structures and recommendations are made for preventing such failures and life losses in the future. In additional to the structural damages, widespread non-structural damages which can make buildings non-functional are investigated. This paper also outlines seismological aspects of the region and characteristics of the recorded strong ground motion.

Time heals all wounds: analysis of changes in temporal focus and implicit space–time mappings among survivors of the 2019 China earthquake over time

abstractAccumulating evidence suggests that people’s sense of the spatial location of events in time is flexible across cultures, contexts, and individuals. Yet few studies have established whether time spatialization is correlated with traumatic experiences. Based on findings that people tend to demonstrate a past time orientation when suffering from disasters, the present research investigated how earthquake experience is associated with temporal focus and time spatialization. Study 1 compared responses of residents in an earthquake-hit area with those of residents in a non-disaster area about two weeks after the disaster had occurred. The results showed that participants in the disaster area were more past-focused and produced more past-in-front responses than participants in the non-disaster area. In Study 2, a follow-up survey was conducted in the same areas ten months after the earthquake to examine whether the impact of disasters on spatial conceptions of time would decay as time elapsed. The findings indicated that participants in these two areas showed no differences in temporal focus and implicit space–time mappings. Taken together, these findings provide support for the Temporal Focus Hypothesis. They also have implications for understanding fluctuation in temporal focus and the high malleability of temporal mappings across individuals.

Evaluating the cognition and response of middle/high school students to earthquake—a case study from the 2013 Mw6.6 Lushan earthquake-hit area, China

Earthquake is one of the most destructive natural disasters in the world. Improving social awareness and the capability of public response is an effective way to reduce the risk and losses of earthquake disasters. This study investigated the capability of earthquake disaster cognition and response (EDCR) based on a questionnaire survey of middle/high school students in the 2013 Lushan earthquake-stricken area. The results indicated that socio-demographic characteristics and prior earthquake experience play important roles in individual's EDCR capability. Female, low age or grade students are more vulnerable to the disaster. Han ethnicity students seem to have more skills for preventing and reducing earthquake disaster and could quickly adjust their emotions after the disasters than other ethnic minority students. Prior earthquake experience has a significant positive effect on the cognition and response to earthquakes, but this effect is gradually weakened over time, due to the loss of disaster experience and memory. Specified disaster education and emergency response drill are important to improve the disaster awareness and emergency response capability of the students, especially for the vulnerable student groups to natural hazards. Due to the importance of school education, it should not only focus on the schools and students education themselves, but also pay more attention to the related families and communities to promote social disaster awareness and improve the general public response capability to disaster.

A Comparative Analysis of Reconstruction Strategies Employed in Major Earthquakes of Indo-Pak Region

Housing is one of the most important needs of mankind to survive. A secure and properly planned house, gives comfort to people using it, keeping them secure from severe environment, un-wanted people and animals. Apart from the human casualties, the other striking and usually most visible effect of natural disaster is majorly the destruction of houses. The loss of houses has a devastating effect on privacy, livelihoods and the dignity of individuals. An effective program for the reconstruction of houses for those affected is critical to ensure restoration of the society’s economy, cultural identity and dignity. For many humanitarian organizations, employing professional construction companies is the most common and quickest way of rebuilding houses in the aftermath of a disaster. However every strategy has its own risks and limitations, but there is a growing awareness being shared among countries to mitigate these situations. This study carefully examines the reconstruction strategies employed in earthquake affected buildings of Kashmir, Pakistan and Gujrat, India. The analysis concludes proper fulfillment of the bye laws for seismic resistant construction and enforcing law of training for laborers and local people in redevelopment of earthquake hit area.

Life satisfaction evaluation in earthquake-hit area by the probabilistic linguistic GLDS method integrated with the logarithm-multiplicative analytic hierarchy process

Occurred on May 12, 2008, the Wenchuan earthquake in China has received worldwide attention for its incredible destructive power. In June of the same year, the State Council issued a draft regulation on post-quake restoration and reconstruction. To find the effect of post-earthquake reconstruction, this paper measures the residents' life satisfaction in Wenchuan by multiple criteria decision-making methods under probabilistic linguistic environment. Based on field surveys and domains of life satisfaction, an indicator system is proposed as a framework to collect resident's evaluations. To retain as much original information as possible, an effective weighting method with probabilistic linguistic information is developed to deduce the indicator's importance. It extends the logarithm-multiplicative analytic hierarchy process to handle the probabilistic linguistic evaluations and derive the criteria weights in interval forms. In this way, the inherent uncertainty of the evaluations on the importance of life satisfaction indicators can be reflected. Furthermore, a novel outranking method named the probabilistic linguistic gain and lost dominance score method, is used to obtain the overall life satisfaction degrees of the residents in Wenchuan. We apply this method to measure the life satisfaction degrees of residents in two areas. The calculation results show that the life satisfaction degrees of the residents in the earthquake-hit area are higher than those of the residents in the non-earthquake area.

Wi-Fi frequency selection concept for effective coverage in collapsed structures

Currently, there is a growing tendency of research on leveraging Wi-Fi signals as sensors for various IoT applications. We observe that most studies deal with the behavior of wireless signals for regular structures in indoor environments. But there is a lack of investigation on Wi-Fi signals behavior for a complex structure like collapsed buildings. This study investigates the possible Wi-Fi signal penetration for collapsed structures. We consider two objectives of this study. Firstly, there is a need to figure out the most common collapsed environments and then to select the best frequency selection concept from available license-free ISM bands to have better coverage. We achieve the first goal through a field survey of an earthquake hit area followed by a debris model constituent of brick and concrete materials. To address the second objective, we have employed two methods for selection of the best frequency. Firstly, we use theoretical bijective soft set approach to select the best available concept and then a modified path loss termed as PL-Collapsed has been introduced to estimate the losses encountered to the wireless signal under debris while providing the best possible coverage with available ISM bands for Wi-Fi. We then compare signal coverage for Wi-Fi bands with each other to finally select the possibly best frequency. Simulation results show that newly introduced Wi-Fi Halow operating at sub 1GHz has relatively better coverage which is also cross-verified by the theoretical bijective soft-set approach. This study triggers the application of wireless signals under collapsed structures where there is a need to rescue the lives. Furthermore, this also prompts new dimensions in IoTs hence emphasizing more ubiquitous systems.

Establishment of unit generation rates of building debris in Kathmandu Valley, Nepal, after the Gorkha earthquake

Significant quantities of building waste were generated from collapsed residential and dilapidated buildings as a result of the disastrous Gorkha earthquake in Nepal on April 25, 2015. In this study, in relation to the field damage investigation of the earthquake hit area and based on the building types, different types of building waste produced from each building are estimated and evaluated. An estimation procedure was established to assess the amount of debris resulting from earthquake. In Kathmandu Valley, different types of buildings generated different quantities of building waste per unit area, and the values for these building types ranged from 1.90 to 3.23 ton m− 2 in weight and 0.89 to 1.57 m3 m− 2 in volume respectively. Residential buildings in Nepal generated a larger amount of waste per unit area (ton m− 2) than buildings in Japan and China. Waste amounts (excluding that in the foundation) generated by public reinforced concrete buildings in Nepal were similar to the amounts generated by reinforced concrete buildings in Japan and China. Wooden buildings had the highest volume per unit area of building waste in Japan, as compared to those in Nepal and Sri Lanka. These results can be used to estimate the amount of building debris that must be cleared for emergency response after a disaster. This information is vital to pre-disaster planning to establish disaster management protocols for smooth recovery operations.

Farmers' risk perception of concentrated rural settlement development after the 5.12 Sichuan Earthquake

Rural housing reconstruction is critical in realizing sustainable recovery. Concentrated rural settlement (CRS) was widely promoted under the context of new countryside construction after the 5.12 Sichuan Earthquake in 2008. Farmers' risk perception of CRS and their corresponding actions affect realizing sustainable recovery. However, few studies have attempted to comprehend farmers' risk perception of such practices, and the impact factors of risk perception remain unknown. Therefore, this study investigates farmers' risk perception of CRS development using four cases in the hardest earthquake-hit area. ANOVA is employed to explore the factors that influence risk perception of CRS development, and in-depth discussions are conducted to explore the reasons behind such perceptions. Potential measures are proposed to reduce relevant risk factors. This study's findings can help local governments in understanding the concerns of farmers toward CRS and in identifying suitable approaches to mitigate risks in order to realize the sustainability of CRS development. This study also provides references for local government to address the specialized concerns when developing CRS within both disaster and non-disaster context.

Characteristics of rainfall responsible for debris flows in Wenchuan Earthquake area

The ability to forecast debris flows is important because of their frequent occurrence and potential for large-scale damage in the Wenchuan Earthquake-hit area. Accurate understanding of the characteristics of rainfall responsible for triggering debris flows is necessary for an effective early warning procedure. This study examined the general characteristics and spatiotemporal variation of rainfall events that responsible for debris flows. Analysis was performed on rainfall data extracted during 2008–2013. The results revealed that the rainfall thresholds for debris flows varied annually and showed tendency toward higher conditions required. The coefficient of variation of relevant rainfall events indicated that the characteristics of the rainstorms changed. In addition, the coefficient of deviation revealed the spatial variation of rainfall in subregions, which was attributed to differences of the local climatic conditions that control debris flow occurrence. The primary controlling rainfall indices for triggering debris flows were filtered, and the most suitable models for establishing rainfall thresholds were selected. Ultimately, the rainfall thresholds were obtained for each subregion within the study area.

Risk assessment of people trapped in earthquake based on km grid: a case study of the 2014 Ludian earthquake, China

ABSTRACTChina is one of the most earthquake-prone countries in the world. The highest-priority mission after an earthquake is to rapidly save lives, and to minimize the loss of life. Rapid judgment of the trapped personnel location is the important basis to identify the emergency supply demands and carry out the search and rescue work after the earthquake. Through analyzing the main influencing factors, we constructed an assessment model of people trapped in collapsed buildings caused by the earthquakes. The accuracy of the estimation results from the model was then tested against the actual investigation data in 2014 Ludian earthquake-hit area. Results showed that, the trapped personnel distribution assessed by this model is generally concordant with that obtained by the actual survey in Ludian earthquake. The grid-based assessment of people trapped in earthquakes can meet the requirements of key search and rescue zone identification and rescue forces allocation in the early stage of earthquake emergency. Although there were some limitations in the study, it offers a simple and rapid approach for assessing the trapped people losses based on basic empirical data. The approach can be further improved to provide more information and suggestions for earthquake emergency search and rescue.

Activity and distribution of geohazards induced by the Lushan earthquake, April 20, 2013

An Ms7.0 earthquake, focal depth 13 km, struck Lushan on April 20, 2013, caused 196 deaths and 21 missing, 13,484 injuries, and affected more than two million people. A field investigation was taken immediately after the quake, and the induced hazards were analyzed in comparison with the Wenchuan earthquake. We have identified 1,460 landslides and avalanches and four dammed lakes, which were generally small and concentrated on high elevation. Avalanches and rockfalls developed in cliffs and steep slopes of hard rocks, including Jinjixia of Baosheng Town and Dayanxia of Shuangshi Town, Lushan, and the K317 section the Xiaoguanzi section north to Lingguan Town along the provincial highway S210. Landslides were relatively less, mainly in moderate and small scales, developing in sandstone, shale, and loose colluviums. Only one single large landslide was observed to turn into debris slide-flow. Dammed lakes were formed by avalanches and landslides, all in small size and of low danger degree. The earthquake-induced hazards distributed in belt on the hanging wall along the faults, and their major controlling factors include tectonics, lithology, structure surface, and landform. More than 99 % landslides were within 30 km to the epicenter, and 678 within 10 km, accounting for 46 % of the total; about 50 % landslides were distributed on slopes between 35A degrees and 55A degrees, and 11 % on slope exceeding 75A degrees; 60 % on slopes at the altitudes between 1,000 and 1,500 m, 77 % on slopes between 900 and 1,500 m; and 24 and 62 % in hard rocks and section between hard and soft rocks, respectively. Compared with the case of Wenchuan earthquake, both the number and extension of landslides and avalanches in Lushan earthquake-affected area are much smaller, only 5.53 % in number and 0.57 % in area. The earthquake has increased the instability of slope and potentiality of landslide and debris flow. Accordingly, the active period is expected to be relatively short comparing with that in Wenchuan earthquake-hit area. However, the insidious and concealed hazards bring difficulty for risk investigation.

汶川地震灾区生物多样性热点地区分析

The Wenchuan earthquake-hit area is located in the Upper Yangtze River,which is the main distribution area of Giant panda(Ailuropoda melanoleuca) in China,and is one of the twenty-five hotspots for biodiversity conservation throughout the world defined by Conservation International,providing some important ecological service functions such as biological diversity conservation,water conservation,soil conservation and so on.Meanwhile,it plays an important role in ensuring regional ecological security.However,the eco-environment suffered from severe destruction in the Wenchuan 5.12 earthquake.In order to protect biological diversity in the Wenchuan earthquake-hit area,it is necessary for us to identify the hotspots for biodiversity conservation,which is of vital realistic significance for the government to devote efforts to reconstruction and is beneficial to optimum resource allocation.Firstly,we calculated the integrated biodiversity index and analyzed the spatial distribution of biodiversity,and then applied the index to determine the biodiversity hotspots by spatial analysis.The hotspots established by the spatial correlation method generally are consistent with the conservation priority area based on the Marxan model.The hotspots account for 76% of the existing nature reserve and the hotspots in Nature Reserve account for 55% of all existing Nature Reserves in the Wenchuan earthquake-hit area,and the total habitat area of all indicator species in the hotspots accounts for about 70% of the whole earthquake-hit area.The verification showed that the spatial correlation method is a reasonable method which can be applied to establishing hotspots.Furthermore,we also found that the spatial correlation analysis method of identifying hotspots is able to overcome the deficiency that the priority area based on the Marxan model is too discrete and islanding.Moreover,the results also showed that there are two biodiversity hotspots,i.e.,the Minshan region and southern Qionglai mountain region.Maoxian Country lies at the junction of the two hotspots in the Wenchuan earthquake-hit area,so it is recommended to set aside a certain natural area as an ecological corridor between these two biodiversity hotspots.The biodiversity hotspots identified by the spatial correlation method can provide the decision-making basis for biodiversity conservation and depressing the influence on biodiversity in the processes of restoration and reconstruction in the Wenchuan earthquake-hit area.

Investigation on building waste and reclaim in Wenchuan earthquake disaster area

A huge amount of building waste was generated by collapsed dwelling houses and dilapidated buildings after the Wenchuan earthquake which occurred on May 12, 2008, in Sichuan Province, PR China. In this paper, based on the field damage investigation in the earthquake-hit area, the relationship between different building structures and building waste produced is established and evaluated. A mathematical model to forecast the amount of building waste in the earthquake-hit area is preliminarily proposed, the type and the quantity of building waste are statistically analyzed from several aspects. The composition and distribution characteristics of building waste in the disaster area are thus described. Finally, considering the characteristics of building waste, some suggestions and applications on potential reuse and recycling of building waste are put forward. This will make the post-earthquake reconstruction engineering more ecological and economical.

Catastrophic debris flows triggered by a 14 August 2010 rainfall at the epicenter of the Wenchuan earthquake

The Wenchuan earthquake of May 12, 2008 produced large amounts of loose material (landslide debris) that are still present on the steep slopes and in the gullies. This loose material creates an important hazard as strong rainfall can cause the development of devastating debris flows that will endanger the resettled population and destroy the result of reconstruction efforts. On 14 August 2010, a total of 21 debris flows were triggered by heavy rainfall around the town of Yingxue, located near the epicenter of the Wenchuan earthquake. One of these debris flows produced a debris dam, which then changed the course of the river and resulted in the flooding of the newly reconstructed Yinxue town. Prior to this catastrophic event, debris flow hazard had been recognized in the region, but its potential for such widespread and devastating impacts was not fully appreciated. Our primary objective for this study was to analyze the characteristics of the triggering rainfall and the sediment supply conditions leading to this event. Our field observations show that even small debris flow catchment areas have caused widespread sediment deposition on the existing fans. It is concluded that the whole of the area shaken by the Wenchuan earthquake is more susceptible to debris flows, initiated by localized heavy rainfall, than had been assumed earlier. The results of this study contribute to a better understanding of the conditions leading to catastrophic debris flow events in the earthquake-hit area. This is essential for the implementation of proper early warning, prevention, and mitigation measures as well as a better land use planning in this area.

P01-143 - Gender differences in prevalence of anxiety disorders among earth quake survivors

IntroductionEarthquake disaster of Pakistan in 2005 caused massive destruction. Death toll was more than 70000. Many survivors were diagnosed as having variable anxiety disorders including panic disorder and PTSD. Frequency of female patients was much higher than male. The major factors responsible are loss of life and property and uncertainty regarding future, harsh weather and repeated tremors.MethodData was collected from various agencies including WHO, Turkish Red Crescent, Canadian team of relief and some other NGOs working with earth quake hit area. Diagnosis was made using semi-structured interviews.ResultsData analyses of women (1056), men (281) and children (204) indicate high prevalence of anxiety disorders including PTSD (853 women, 153 men) and depression (73 women, 31 men). Results vary from the observations made from other disasters. Sex ratio shows huge difference in prevalence between males and females.DiscussionPatients with PTSD have dysregulation of HPA axis response. This alteration is more pronounced in case of women. Studies show that estrogen plays important role in the genesis of disease. Dexamethasone suppression test also indicates greater dysregulation of glucocorticoid receptor. Studies reveal predisposition in women for PTSD and depression.Women and children were affected most because most of them were at home and in schools. Hence, they sustained more physical injuries and psychiatric consequences.In our study depression came out to be more prevalent in females. This can be explained as comorbidity of PTSD and because of its own dynamics.ConclusionAfter exposure to trauma male and female respond differently.

Numerical simulation and analysis for collapse responses of RC frame structures under earthquake

In this paper, a discrete element model for collapse simulation of RC frame structure is constructed by discretizing the structure into a few elements and spring groups. This model introduces special hysteretic models of connected springs for arbitrary loading path and also takes into account reasonable failure criteria for springs considering coupling effect of shear and axial force. Based on the discrete element model, a computer program is developed to simulate the whole process of RC frame structures from initial state to collapse under earthquakes. Particularly, the contact-impact problem between discrete elements has been treated with effective measures. Then, the program is employed to study the collapse mechanism of a real building in Wenchuan earthquake-hit area; the result of which shows that the simulation program developed based on the new model can realistically simulate the seismic collapse process of RC frame structures.

Monitoring and assessment of barrier lakes formed after the Wenchuan earthquake based on multitemporal remote sensing data

The Wenchuan earthquake on May 12, 2008, triggered many secondary disasters, among which the barrier lakes formed by landslides were extremely serious. We monitored the number and spatial distribution of the barrier lakes in the earthquake-hit area from ADS40 airborne images, which covered areas of about 23,700 km2. The results showed that there were 51 barrier lakes in the monitored area; among these, 10 were large-scale lakes and 14 were middle-sized lakes. The barrier lakes were distributed along the Longmen Mountain fault from the northeast to southwest direction. We used the dimensionless blockage index (DBI) to assess the potential risk of the barrier lakes. A small DBI value indicated a stable barrier lake, but the lake might have a higher risk with potential accumulative secondary disasters. Our study emphasized the monitoring and analysis of the high-risk Tangjiashan Barrier Lake from the multitemporal ADS40 airborne images acquired on May 16, 19, 23, and 27. We found that the water level at this barrier lake reached 66 m within 15 days after the barrier lake was formed, and the reservoir storage capacity reached 1.2 × 108 m3 with an increase of 8 × 106 m3 of water per day. Therefore, it faced a very real and urgent risk of dam break and overflow, considering the predicted storm rainfall and the continuous aftershocks. According to the analysis results, airborne remote sensing demonstrated the advantages of being intelligent, being able to maneuver, and providing high resolution. These advantages allowed us to quickly monitor and assess the distribution and dynamic changes of the barrier lakes in the earthquake-hit region using multitemporal airborne remote sensing images.

Trauma care of evacuated earthquake casualties: experience of a rear hospital

Objective To discuss our experience of trauma care of earthquake casualties evacuated from the earthquake-hit area in Sichuan province. Methods In this study, the medical records of 53patients who had been transferred to our hospital after the 5.12 Sichuan earthquake were analyzed retrospectively. Of them, 33 were assigned to the department of orthopedics. Twenty-nine were treated surgically and 4 conservatively. Results All the patients healed with good outcome and no severe late complications related to fracture or surgery were observed. No death occurred. Conclusion In treatment of earthquake casualties, many jobs should be taken into consideration and practice, including efficient organization, systematic and careful diagnosis, individualized treatment, psychological consultation and prevention of late complications. Key words: Earthquake; Trauma; Treatment