Publisher(s): China Academic Journals (CD Edition) Electronic Publishing House Co., Ltd.
ISBN: ISBN 978-7-499-00988-2 pdf
First Published: 2020.11.23
Discipline(s): Chemistry/ Metallurgy/ Environment/ Mine Industry
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Natural Disasters and Disaster Prevention, as part of China’s S&T Progress Series, has 143 excellent Chinese articles on natural disaster research. This collection of articles involves the latest findings in natural disaster research supported by National Natural Science Foundation of China, National Key R&D Program of China and National Major Scientific Research Program of China. These articles involve the disaster examples such as 5.12 Wenchuan earthquake, 4.25 Nepal earthquake, Typhoon Maria and Typhoon Rammasun and comprehensively demonstrate the successful experience and countermeasures in dealing with major natural disasters in China. This book is a compilation of the English version of the selected Chinese articles and includes six chapters, with detailed introduction of the formation mechanisms, risk assessment, monitoring and warning, and disaster mitigation measures of six types of natural disasters: earthquake, drought, flood, typhoon, landslide and debris flow. It provides scientific and technical support for understanding the patterns of disaster occurrence, predicting the future disasters, and mitigating the harm caused by natural disasters.
LIU Jingnan, academician of Chinese Academy of Engineering and professor and doctoral supervisor at Wuhan University, has long been engaged in the theoretical and applied research of geodetic surveying and teaching.
1. Disastrous spatial distribution and danger zonation of secondary geological disaster in Xizang after "4·25" M s 8.1 Nepal earthquake
Journal of Natural Disasters,Part 1: Earthquake,Vol 26,No. 01
Based on a large number of data of geological disasters field survey and multisource interpretation of remote sensing images, we obtained 899 geological disaster sites. We firstly selected 9 influence factors including landform, geology, earthquake, meteorohydrology and mankind activity, and then conducted statistic analysis of spatial distribution law of geological disasters and each factor by use of GIS technology. Assessment and zonation of secondary disaster danger were carried out on the basis of K-prototypes clustering analysis and maximum likelihood classification. Results show that the geological disasters in disastrous area are not same for different kinds of disaster, and present discontinuous concentric distribution. Among the disaster danger, medium, high and extreme high danger are dominant ones, and they account for 35.10%, 21.67% and 24.38% respectively, extreme low and low danger area account for 18.85%. There is a better positive correlation between spatial distribution of disaster site and danger class of disaster. This verifies directly zonation results of the danger.
Journal of Natural Disasters,Part 1: Earthquake,Vol 24,No. 02
This paper analyzes the spatio-temporal distribution feature of historical earthquake disasters in Gansu Province based on GIS platform, to provide a scientific basis for seismic hazard assessment and emergency rescue work. The results showed that: (1) Gansu Province has occurred 188 violent earthquakes (M ≥ 4.75) in the history,and these earthquakes distributed in 59 districts and counties throughout 13 cities and prefectures, (except Jinchang City). There was no significant spatial differentiation of earthquakes disaster in Gansu Province; (2) The large earthquake influence degree has considerable regional difference,and based on this difference,Gansu Province can be roughly divided into two areas: Hexi and Hedong regions. The epicenter intensity and affected area of an earthquake with same magnitude is smaller in Hexi region than those in Hedong region; (3) Regional seismicity fluctuates periodically and 3 especially serious earthquake disasters( M ≥ 7.0) occured during 1917–1936, i. e. the most frequent seismic activity phase over the past century in Gansu Province. At present, Gansu Province is in another earthquake active period; (4) Casualties caused by the earthquake show regional difference,and the casualties caused by an earthquake with same magnitude are more serious in east river region than that in west river region. With relatively large proportion of the rural population,the earthquake disaster in Gansu Province is more serious than that in other economic flourishing provinces.
3. The characteristics of earthquake disasters distribution and seismic damage to structures in Kangding M s 6.3 earthquake
Earthquake Engineering and Engineering Dynamics,Part 1: Earthquake,Vol 37,No. 03
Kangding lies in the northwest of Sichuan of China, and the Tibetan population accounts for 70%. The seismic intensity design of Kangding region is IX degrees. There are numerous Tibetan stone-wood structures, Chuandou-type timber frames, masonry structures and reinforced concrete (shear) structures in Kangding region. The extent of damage has a huge difference among various types of structures in M s 6.3 Kangding Earthquake. Through the 17 settlements investigation in 3 survey zones, in this paper, the proportion and distribution of various types of structures are counted, and the construction methods, cost, damage features and average damage indexes are also analyzed with a detailed investigation and statistics. The results show that, Tibetan houses generally adopt stone-wood mix load owning to lack of building materials, and are damaged in different degrees in various intensity zone. While the Chuandou-type timber frames, the fortified masonry structures and reinforced concrete (shear) structures are mostly intact because of excellent seismic capacity. The paper analyzes earthquake buildings damage characteristic of different structure type, and at the same time, gives a preliminary suggestion about the construction mode of Tibetan buildings.
4. Investigation and analysis of seismic damage to school buildings in M s 7.0 Jiuzhaigou earthquake
Earthquake Engineering and Engineering Dynamics,Part 1: Earthquake,Vol 38,No. 04
After the M s 7.0 Jiuzhaigou earthquake in Sichuan Province, China, during the earthquake emergency rescue, we carried out a detailed investigation of seismic damage about 106 buildings in 27 primary and secondary schools as well as kindergartens, and collected the survey and design data. Through the statistic analysis of the seismic damage data, we summarized the characteristics of seismic damage, evaluated the building damage grade, and discussed the reason of the serious damage to the building of the Zhangza Primary School, and then gave the suggestions about how to strengthen the capacity of protecting against and mitigating earthquake disasters in schools. The purpose of the investigation is to ensure the normal operation of school teaching tasks in the disaster areas, reduce the school’s burden greatly, promote the development of resisting earthquake, provide disaster relief, and enhance the confidence in continuing to implement the policy of “School Safety Engineering”.
5. Data processing and analysis of strong ground motion records of the 2017 M s7.0 Jiuzhaigou earthquake
Earthquake Engineering and Engineering Dynamics,Part 1: Earthquake,Vol 38,No. 05
The strong motion data from the Jiuzhaigou earthquake of August 8, 2017, were collected and processed. In order to get the standard format acceleration, we transformed the data format of the original data, corrected the baseline, and complemented the metadata before the normal analysis and processing. There are 46 pieces of acceleration larger than 10 Gal, The PGA varied from 0.33 to 185.02 cm/s 2and the PGV varies from 0.04 to 6.55 cm/s. The maximum instrumental seismic intensity is 6.2 in China seismic intensity scale. We compared the observed PGA and PGV with the Chinese attenuation relationships used in the seismic ground motion parameter zone map. It showed that the observed PGA and PGV within the 200 km were consistent well with the Yu 2013 short-axis PGA and PGV prediction attenuation relationship, but it decayed slower than the relationship with epicenter distance larger than 300 km, and the possible reason was proposed. The two largest response accelerations were analyzed, the response spectrum of the NS component of 51JZB was larger than the seismic design response spectrum of 7-degree rare earthquakes in China. The peak period of the acceleration response spectrum was mainly between 0.1 s and 0.4 s at 51JZB and 51JZW, so it would not cause severe damage to the long period buildings. The 5%–75% significant duration and 5%–95% significant duration were calculated, the significant duration grew with the epicenter distance in the whole.
Earthquake Engineering and Engineering Dynamics,Part 1: Earthquake,Vol 35,No. 06
This article defined the contents of the policy of earthquake early warning, and proposed goals, guidelines and research methods of the policy of earthquake early warning. This article also summarized policies and methods that Japan has used to develop and apply earthquake early warning system (EEWS). Considering the inadequacies of the EEWS in China, and using the experience of other countries for reference, this article predicts some potential problems and analyzes the reason of the problems during construction and application of EEWS in China. Besides, in order to solve these probable problems, a preliminary policy frame and classification system for EEWS has been established, and some advices has been raised to build better organization management, laws, regulations and industry standards, innovations, publicity, application, information management and publish, financial investment. In addition, different suggested time tables for these different policies have also been raised. This article has offered many reference opinions for better development, construction, management and policies of EEWS in China.
7. Research on new early-warning method of earthquake and analysis of earthquake early-warning ability
Earthquake Engineering and Engineering Dynamics,Part 1: Earthquake,Vol 39,No. 07
In this paper, we propose a new earthquake early-warning method, which is different from the traditional method. For this new method, we apply data assimilation to estimate the accurate distribution of the present wavefield and simulate the propagation of wave energy numerically by the direct simulation Monte Carlo method based on Radiative Transfer Theory. Then we calculate the intensity of the target area and issue the alert after judgment. There is no seismic phase collecting, no seismic location, no magnitude, and no ground motion prediction equation in the new earthquake early-warning method. Depending on this technique, we avoid the accumulation of errors resulted from a series of techniques based on empirical statistical rules in traditional method effectively and get rid of the limitation of relying on P-wave purely when faced with a complex earthquake. We select two events, i.e. the 2011 M w9.0 Tohoku earthquake in Japan and the 2016 M w6.7 Meinong earthquake in Taiwan, for case analysis and to probe deeply into the capacity of this new method used in the earthquake early-warning system. What’s more, earthquakes occurred in or out of the seismic station network and complex earthquakes are taken as the scenes in the analysis. Then as a conclusion, we find the new method behaves well in earthquake early-warning when faced with the earthquakes occurring in the seismic station network and has a great advantage in dealing with complex earthquakes compared with the traditional verification method. In the end, we summarize and discuss the shortcoming of the research work.
Progress in Geophysics,Part 1: Earthquake,Vol 30,No. 08
In this study, we proposed the principles for preliminarily dividing interplate seismogenic zones and testing its reasonableness based on the brittle failure theory of multiple locked patches in a seismogenic fault system and divided the Circum-Pacific seismic belt into 15 seismic zones based on these principles. In addition, we analyzed the seismogenic process of the large or great earthquake events in these zones from the angles of the definition of seismogenic period and the recognition of the main shock event, and predicted the future earthquake situation. The results showed that the seismic zones of Taiwan Island–Philippines as well as Ryukyu Islands–Taiwan Island have reached their critical states and great earthquakes can occur at any time; great earthquakes will occur in the seismic zones of Aleutian Islands–Vancouver–San Francisco Guadalajara, Mexico City, Bogota–Arica–Valdivia, Suva Wellington, New Guinea–Solomon islands, Java–Maluku islands, Northern Mariana Islands and Hokkaido–Kamchatka; a large or great earthquake will occur in the San Salvador–San José seismic zone; a major earthquake will occur in Melekeok seismic zone; the M W 9.1 earthquake occurred in Sumatra seismic zone in 2004 and the M W 8.6 earthquake occurred in Chagos Archipelago seismic zone in 2012 were main events; Southern Panama City is a dangerous seismic zone with no less than M W 7.2 earthquake. Our results provided a reference for the relevant departments of relevant countries in Circum-pacific seismic belt to take effective measures for earthquake disasters reduction. Analyses of the above cases indicated that like shallow focus earthquakes, deep focus earthquakes may have similar seismogenic mechanism and are resulted from brittle fractures of multiple locked patches.
Earthquake Engineering and Engineering Dynamics,Part 1: Earthquake,Vol 36,No. 09
In order to predict the intensity quickly and accurately after the earthquake, we proposed a real-time prediction method using shape function. After the earthquake, the intensity can be calculated in real time, and the increase of which can be described as functions. In this paper, we use four functions to show the change of intensity and then get the parameters of each function. The 1821 strong motion stations’ records of 352 seismic events from Ki K-net in Japan were used in order to find the correlation between epicentral distance and parameters. In this method, epicentral distance of a station should be calculated at first, and then we get the parameters in four functions. At last, we predict the final intensity of the station during the earthquake. The results show that by taking the method proposed in this paper, the accuracy of the intensity prediction is improved, especially for the stations whose epicentral distance between 50 and 150 kilometers. On the other hand, it is not suitable to use this method for those stations with epicentral distance lower than 50 kilometers.
Progress in Geophysics,Part 1: Earthquake,Vol 31,No. 10
Electromagnetic method is one of the earthquake prediction methods which is in the preliminary stage. The main process of this method is to acquire the electromagnetic data (electric components, electrical resistivity, magnetic components or the electromagnetic wave of given frequency, etc.) in the areas that are covered with observation instruments. The data were processed to extract the electromagnetic anomaly caused by seismic activity. The earthquake predictions including time, location and magnitude of the earthquake are suggested by analyzing the electromagnetic anomaly. Many experiments and studies showed that electromagnetic method for earthquake prediction is not effective yet, and its precision and the range it can predict are extremely limited. Finding out the physical mechanism of the electromagnetic anomalies before the earthquake and its relation with the three elements of earthquake are the main tasks and it will be a big step for earthquake prediction. In this paper, we reviewed the development and prospects of electromagnetic method in earthquake prediction all around the world from three aspects: the basic experimental results of the rock fracture process, the field observation records and the analysis as well as the evaluation of the existing electromagnetic methods.
Progress in Geophysics,Part 1: Earthquake,Vol 33,No. 11
The geochemical prediction method is a common method for predicting earthquakes. By studying the anomalous changes of geochemical components before earthquakes and getting the law, the relationship between them and the three elements of earthquake will be deduced. The gas geochemical method is applied to predict earthquakes by using the gas anomalies before earthquakes. Because the degasification of the Earth has always existed, the rock mechanics properties of the rock in the epicentral area before the earthquakes are greatly changed, resulting in a large amount of fluid gushing, and the active faults with better permeability provide a channel for the deeper fluids easier to reach the surface, causing the anomalies of soil gas (the fault gas) in the surface fault zone, which provides the basis for earthquake prediction. The major components of gas and geochemical anomalies are soil radon, H 2, CO, CO 2, etc. These gas measurements show obvious anomalies before earthquakes, most of which are sudden jumping rises, decreases, abnormal amplitude rises, abnormal periods increasing and so on. We analyze the characteristics of these anomalies, from the three elements of earthquake, we determine the relationship between the two, so as to evaluate the gas chemical earthquake prediction method. Because of the good gas activity, it is easy to bring the underground seismogenic information to the surface. The gas chemical abnormalities are of high reflection, so the method rarely false. But there are possibilities of omission, so it is hard to make right prediction using this method only, still needing to combine other methods to increase the accuracy of earthquake prediction.
Progress in Geophysics,Part 1: Earthquake,Vol 33,No. 12
Geochemical anomaly monitoring is one of the earthquake prediction methods, which is aim to find out the relationships between the earthquake’s three elements and the geochemical anomalies’ changes, and then predict the earthquake. The existing geochemical methods can get the time, place and magnitude of the earthquake by studying the geochemical anomalies which include hydro-chemical, gas chemistry and soil chemical anomaly. Because the water and gas are the medium of rocks and the sensitive components to reflect the rocks deformation, the anomaly of hydro-geochemistry is the most common geochemical anomalies before earthquake. The common hydro-?geochemical prediction method monitors gas composition (radon, hydrogen, and helium) in the groundwater, quality components (B, F, Li, and Sr), abnormal chemical and physical water conductivity, water temperature and water level, abnormal changes of anomalies in some stable isotope ratios (He 3/He 4 and Ar 40/Ar 36) and conducts the statistical analysis, combined with the relationship between the rock mechanics experiment so that we further get the relationships between hydro-chemical anomalies and earthquakes’ “three elements” and obtain the earthquake prediction opinions. This article includes the current situation of hydro-geochemical prediction and some hydro-chemical earthquake predictions, we analyze the characteristics and seismic results of several hydro-geochemical anomalies and the physical and chemical mechanism of hydro-chemical anomalies, such as rock fracture mechanism, mixing mechanism, vibration mechanism, pressure dissolution mechanism, then summarize the main anomalies feature, and evaluate the research progress and development prospect of hydro-geochemistry earthquake prediction method by combining monitoring examples and many factors affecting hydrological earthquake prediction.
13. Application of a threshold-based earthquake early warning to Italy M W6.2 earthquake on August 24, 2016
Earthquake Engineering and Engineering Dynamics,Part 1: Earthquake,Vol 37,No. 13
We introduced the concept and process of the threshold-based earthquake early warning method. We analyzed the universality of this method using the near-field strong-motion data recorded in the Italy M W6.2 earthquake on August 24, 2016. Our results indicated that the alert level of each station can be accurately predicted and the extent of the potential damage zone (PDZ) can be rapidly estimated after the first station triggered. The determination of alert level for each station and the estimation of the potential damage zone showed reasonably good agreement with the distribution of instrumental intensity of Shake Map from the U.S. Geological Survey (USGS). The feasibility and validity of this method in Italy M W6.2 Earthquake on August 24, 2016 were demonstrated.
Journal of Natural Disasters,Part 1: Earthquake,Vol 24,No. 14
Using information from single station to identify seismic events and interference in a short time is a key issue in an earthquake early warning system. Based on characteristic parameters of the waveform, this paper studies the application of the decision tree method for improving the anti-interference ability of a single station in an earthquake early warning system. In order to study the influence of electromagnetic interference on earthquake early warning systems, seven kinds of electromagnetic interference were tested in this paper. Five features (whether the event ended, Speed, Sparse, Pration, Symmetry) were extracted from waveform data in 3 s after an event trigger, and the relationship between feature values and the type of events was established by a decision tree. The paper uses numerous strong-motion records and interference records (6359 seismic records and 163 interference records) to validate the trained decision tree, and the results show that this method achieves a high recognition rate. This algorithm is easy to convert to IF-THEN rules and can easily be written in computer programs or expert systems. This algorithm could be used as the seismic event detecting module for earthquake early warning or alarm systems to improve their reliability.
Journal of Natural Disasters,Part 1: Earthquake,Vol 25,No. 15
Masonry structure is an important structure type of building in China, and its seismic damage prediction is an important content of earthquake prevention and disaster reduction. By now, there have been various methods of seismic damage prediction of single masonry structures. In this paper, the seismic damage prediction methods of single masonry structures were introduced and reviewed such as semiempirical-semitheoretical method, strength judgment method, historical seismic damage statistics method, specialist evaluation method, fuzzy analogy method, structural theory calculation method, and dynamic analysis method. Then the paper makes seismic damage predictions about seven multi-story masonry structures of Leigu Town, Beichuan County in the Wenchuan earthquake, and comparatively analyzes the predicted results from different methods. Finally, the paper makes some exploratory discussions for the research of seismic damage prediction on masonry buildings.
Progress in Geophysics,Part 1: Earthquake,Vol 34,No. 16
We introduced a new Mobile Oceanic Seismic Recording System (MOSRS) for long-term P-wave recording. Compared to the traditional stationary land seismic station or ocean bottom seismometer (OBS), the MOSRS will float in the seawater with a given depth and move along with ocean currents after deployment. When an earthquake occurs, the MOSRS will record the P-wave seismic data and rise to the sea surface automatically. After transferring the recorded seismic data to shore-based Satellite Receiving Stations, the MOSRS will submerge to the given depth again and continue the P-wave seismic data recording. This MOSRS is a modular design system with five modules: the hydrophone, the buoyancy control system, the communication and transfer system, the energy system, and the central control system. A shore-based monitoring system is also designed. The MOSRS is able to record the long-term P-wave seismic data from much wider regions in a near-real-time manner, which can break through the technical limits of recent marine seismic recording devices and provide accurate and reliable seismic data for the seismic tomography imaging of the deep structure.
Progress in Geophysics,Part 1: Earthquake,Vol 34,No. 17
The near-surface crustal structure is closely related to human production and life. Accurate reconstruction of the velocity structure of shallow crust by seismic tomography can help us to carry out high-precision seismic exploration, explore shallow resources and minerals, avoid potential natural disasters, and construct urban underground space. Complex surface conditions are widely found in China’s mainland, especially in the basin-range junction zone of central and western China, which poses a serious challenge to accurately reconstruct the velocity model of shallow crust. This paper systematically discusses the basic principle, existing problems and development direction of two types of current seismic tomography methods, namely, traveltime tomography method based on high frequency approximation theory and on the finite frequency tomography theory. The former is based on the high frequency approximation theory of seismic rays. According to whether there is explicit ray tracing in the forward calculation, it can be divided into the conventional traveltime tomography method and the traveltime tomography method without ray paths. The conventional traveltime tomography method utilizes the traditional ray tracing methods. When the near-surface velocity changes strongly, the imaging distortion is usually caused by the existence of shadow zone or multipaths, which seriously affects the imaging efficiency. In contrast, the traveltime tomography method without ray paths calculates the sensitive kernel directly by forward and backward propagation of the traveltime field of the eikonal equation, and obtains the gradient of the objective function by the adjoint state method, which has the advantages of fast speed and robustness. Since the band-limited property of the seismic wave frequency is not considered, there are some problems of the traveltime tomography based on high frequency approximation theory, such as wave scattering, wave front healing and poor inversion constraint. The latter, i.e., the finite frequency tomography, overcomes the drawbacks of the assumption of “infinite high frequency” in ray theory and has become more important. The methods are mainly divided into ray finite frequency tomography method and the finite frequency tomography method based on wave equation. Ray finite frequency tomography can improve the resolution of imaging, but in essence, it still depends on the ray theory and is difficult to deal with complex wave phenomena. The finite frequency tomography method based on wave equation can accurately deal with complex geological problems, improve imaging reliability and visually display the velocity structure of seismic waves in the earth’s interior in the form of images. However, this method strongly depends on sufficient low-frequency information in data or a more accurate initial velocity model in practical applications, and its wide application requires further exploration and development.
Chinese Journal of Geophysics,Part 1: Earthquake,Vol 62,No. 18
The development of efficient, high-precision, and universal automatic waveform pickup algorithm is more and more important in the background of earthquake big data. The main challenge comes from how to adapt to the classification of different types of seismic events in different regions. In this paper, according to the seismic event-noise classification problem, a convolutional neural network method was used to train the dataset based on 13839 Wenchuan earthquake aftershocks and 8900 new Wenchuan aftershock events were used as the test data set. The training and detection accuracy rates were both over 95%. In the detection of continuous waveforms, the CNN method was superior to the traditional methods of STA/LTA and Fbpicker inprecision and recall rate, and can find a large number of manually selected microseismic events that were easily missed. Finally, we used the trained optimal model to identify 8-day continuous waveform data from 441 stations nationwide. CNN detected 7016 waveforms, then we picked up 1 380 pairs of P and S arrival times using an automatic picking algorithm, finally the pick-ups were successfully associated with 540 earthquake catalog events. The overall recognition accuracy of events above magnitude 1 was 54% and 80% above magnitude 2, while in some areas such as Sichuan and Xinjiang the detection rate was higher. It is shown that CNN neural network had broad application prospects in the real-time earthquake detection and location.
Journal of Natural Disasters,Part 1: Earthquake,Vol 25,No. 19
Evaluation system of earthquake emergency management capacity is the most intuitive judgment of the earthquake emergency management level for a zone. There are several factors influencing the earthquake emergency management capacity, whose scientific degree, to a certain extent, ensures the effectiveness of the evaluation system. Firstly, from the perspective of emergency management time axis, 16 factors based on three aspects of the earthquake emergency management capabilities were cleared. Interpretive structural model (ISM) was introduced, and criterion comparison matrix and reachability matrix were constructed among the factors. Moreover, area and level division was made, and therefore the assessment system of earthquake emergency management capability was built to ensure the indicators’ independence in the same level. Results show that most of the deep-hierarcy factors belonging to pre-earthquake preparedness capacity system, influence the surface factors belonging to earthquake response capacity and post-earthquake recovery capacity system. Finally, FCE is chosen to research empirically on the evaluation system through taking Wenchuan earthquake as an example.
20. Correlation analysis of PGA amplification factor with site characteristic parameters and fast assessment of ground motions
Earthquake Engineering and Engineering Dynamics,Part 1: Earthquake,Vol 37,No. 20
The PGA amplification factor F PGA is a basic index for ground motion prewarning of important engineering structures and the seismic input of engineering structures design. Selecting 239 seismic stations from Kik-Net, Japan, and the records recorded at the stations which are on site class II, the correlation of F PGA with respect to site characteristic parameters, i.e., the site thickness D, site characteristic period T, v s30 and equivalent shear wave velocity v se, are studied under different ground motion intensity which is represented by the input PGA values. Taking ground motion PGA 40 gal as the target prewarning threshold, the parameters combinations are presented using the classification and regression tree (CART) method. The analytical results show that F PGA is negatively correlated with D and T, but positively correlated with v s30; v se has a quite weak correlation with F PGA; the correlation of site characteristic parameters and F PGA is strengthened with increasing input intensity; by means of the CART method, the ground motion prewarning criterion is tested on the selected Kik-net data that the total success rates keep 90.09%, including 93.64% of non-prewarning and 82.68% of prewarning. Albeit the total success rates of the criterion are greater than 90%, 5.61% of the prewarning data are omitted, which could be dangerous. Therefore, the method presented herein should be improved.
Journal of Natural Disasters,Part 1: Earthquake,Vol 24,No. 21
To solve the problem of the loss assessments in earthquake emergency stage, the allocation of post-disaster rescue workers and supplies, the analysis of rescue path and a series of important issues during earthquake emergency,combining with the attenuation relationship of earthquake intensity in Fujian Province, by means of GIS, the seismic intensity and influence scope under different earthquake magnitudes and rupture directions were displayed in a visual form. According to the simulation results of earthquake intensity distribution,combining with the visual interpretation of remote sensing image, we can quickly judge the earthquake location,scope and the disaster loss situation and the passible developing trend of the disaster. Finally, through analyzing the shortest rescue route and watching the video shot and 360° panoramic scene, etc. of earthquake scene, policymakers can really feel the disaster situation,and adjust the rescue force in time,which could improve the accuracy and scientificity of decision-making. The system can also provide certain reference for seismic departments at all levels to improve earthquake prevention and disaster reduction information system, and promote their work to be more systematic and reasonable.
22. Secondary mountain disasters induced by the "4·25” Nepal earthquake in Nyalam County and disaster prevention and mitigation countermeasures
Journal of Natural Disasters,Part 1: Earthquake,Vol 25,No. 22
Extraordinary earthquake disasters were caused by the "4 ·25” Nepal earthquake, and meanwhile a great number of secondary mountain disasters whose main types include collapse, landslide, debris flow, unstable slope, etc. were induced by the earthquake. These secondary mountain disasters not merely resulted in heavy casualties but also seriously affected safety operation of the China-Nepal highway (Line G318) and Nyalam Town, Zhangmu Town (port). Large quantities of collapses and landslides induced by the earthquake supplied debris flow with abundant material sources which is a big stimulus to yielding catastrophic debris flow hazards under heavy rain in the later days. The results are as follows through preliminary analysis: (1) there are 221 secondary mountain disasters induced by the "4·25” Nepal earthquake including 10 landslides, 159 collapses, 26 debris flows, 26 unstable slopes in the Nyalam County, and these secondary mountain disasters are distributed in five towns. (2) Regional disasters is given priority to with landslide, collapse along Nyalam town to Friendship Bridge; Regional disasters is given priority to with collapse, debris flow along Nyalam town and Yalai town to Dadi; Finally, disasterprevention and mitigation measures of restoration and reconstruction in the earthquake zone are proposed combined with the topography, geological structure, and meteorological conditions of the region.
Journal of Natural Disasters,Part 1: Earthquake,Vol 25,No. 23
How to perfect emergency capability efficiently and carry out comprehensive disaster prevention planning is an important issue that earthquake emergency preparedness work faces in China. It is the best way to build a comprehensive emergency response capability abroad that taking the potential disaster scenarios as the goal of emergency preparedness, and then making a disaster prevention plan. According to the ideas of constructing scenarios, this paper introduces a framework of earthquake catastrophe preparedness plan suitable for the emergency response system in China. The framework describes the potential risk as a quantitative model of earthquake scenarios, sorts out the emergency task, and evaluates the emergency response capability by analyzing disaster scenarios. Finally, it makes an emergency defense plan and work suggestion, which has a certain reference sense for the Chinese earthquake emergency preparedness system construction.
Earthquake Engineering and Engineering Dynamics,Part 1: Earthquake,Vol 37,No. 24
Huge economic loss and social loss would be caused when the bridge was damaged in the earthquake, which was regarded as an important part of lifeline engineering. Due to the dynamic characteristics and the spatial variation characteristics of the ground motion, vibrations in different directions between the adjacent bridges were caused during the earthquake. During seismic events, poundings between the adjacent bridge components can occur when the relative displacement is larger than the expansion gap. On the other hand, unseating failure occurs when the expansion gap size is too large. Based on the pounding and unseating phenomenon between the adjacent bridge segments, the damages of the previous earthquakes were reviewed. The state of pounding and unseating mitigation measures including restrainers, damping devices, modular expansion joints, shock absorbing device and hybrid devices were presented. The merits and limitations of these measures were summarized systematically, and some topics which were worth studying further were proposed.
Earthquake Engineering and Engineering Dynamics,Part 1: Earthquake,Vol 37,No. 25
The earthquake resilient structure is the structure which can restore the structural function immediately after a severe earthquake without significant repair, which has been a new research direction in the field of earthquake engineering and has attracted more and more attention by the related scholars and technologists. The 16th World Conference on Earthquake Engineering was held in Santiago, Chile in January of 2017, whose theme was “Resilience, the new challenge in earthquake engineering”. In this paper, the research advances in the field of earthquake resilient structures shown by this conference are summarized, focusing on the rocking and self-centering structure and the structure with replaceable components. The research progress of the application of earthquake resilient structures in moment frame structures, shear wall structures, frame-shear wall structures, bridge structures is introduced. The results of considerable experimental study and numerical analysis have verified the good seismic performance of resilient structures. Based on the above reviewing results, the research orientation and prospect in the future are discussed finally.
Earthquake Engineering and Engineering Dynamics,Part 1: Earthquake,Vol 37,No. 26
Seismic resilience research has become a detailed and deepening hot point in the field of earthquake engineering and disaster prevention and mitigation. As the relevant seismic performance of nonstructural systems could decide the functional level of engineering construction, performance-based seismic study of nonstructural systems can be the key point of seismic resilience research, which has also caught high attention of earthquake engineering researchers. Based on related research results published in 16WCEE meeting, this paper introduces basic concept and development of seismic resilience, and research advance of concept and frame of both building facilities and community seismic resilience. The paper also summarizes latest research findings on the evaluation methods of seismic resilience and related nonstructural systems, and the test/design methods and seismic devices of nonstructural components. The research directions of both seismic resilience and associated performance-based seismic study of nonstructural systems are finally proposed.
Journal of Natural Disasters,Part 1: Earthquake,Vol 27,No. 27
In order to further study the seismic performance of existing rural buildings in Jiangxi, based on the existing seismic investigation data and preliminary analysis results, taking three typical buildings for example, the elastic-plastic finite element analysis was carried out. For a typical masonry structure damaged in the Jiujiang-Ruichang earthquake in 2005, its seismic damage characteristics were analyzed and its elastic-plastic finite element analysis was carried out, by comparing with actual seismic damage, the validity of the finite element model was verified. Then the seismic performance of rural buildings in early Jiangxi was discussed. On the basis of these, its impacts on the seismic performance of masonry structures were analyzed after adding structural columns and ring beams and increasing the strength of mortar. One typical rural masonry structure and frame structure in Jiangxi were selected respectively to carry out the finite element analysis. Based on the survey data and the prediction results of earthquake damage, the present situation of seismic performance of rural buildings in Jiangxi was reviewed. The results showed that the seismic performance of rural buildings in Jiangxi has improved after the Jiujiang-Ruichang earthquake in 2005, the existing rural buildings investigated in Jiangxi basically met the local seismic fortification requirements. The seismic performance of masonry structure can be improved effectively by adding structural columns and ring beams and increasing the strength of mortar.
Journal of Building Structures,Part 1: Earthquake,Vol 39,No. 28
Since population and social wealth are concentrated in large cities and urban areas, the seismic safety issue of cities threatens the implementation of the new urbanization in China. Disaster vulnerability has become a critical issue that restricts the sustainable development of cities in the process of urbanization, and it has been the consensus in the field of earthquake engineering worldwide to build resilient engineering facilities, cities and society. The research of city seismic resilience is a challenging project which involves multi-disciplines, such as seismology, civil engineering, artificial intelligence, remote sensing technology, sociology, economics, management and so on. This paper proposes the scientific definition of city seismic resilience, summarizes the current research status of city seismic resilience evaluation in the world systematically, and puts forward the scientific and technical issues related to building seismic resilient cities and strategies to improve the capacity of resilience.
Earthquake Engineering and Engineering Dynamics,Part 1: Earthquake,Vol 37,No. 29
The differences of seismic fortification levels existed in those structures built in different time and different areas would introduce some deviation to the seismic vulnerability matrix when one try to assess seismic vulnerability of urban buildings based on the encountered intensities. To solve the problem, the concept of intensity gap is introduced to assess the seismic damage of typical cities based on field observation datum. A comparison of seismic vulnerability matrix of urban buildings based on intensity gap and those based on encountered intensity is carried out. And meanwhile, another comparison of the seismic ability indexes based on intensity gap and those by the finite element analysis results is also carried out. The results show that the seismic vulnerability matrix of urban buildings constructed through intensity gaps can better reflect the seismic damage. The seismic ability index of urban buildings based on intensity gap is basically consistent with that by simulation. Intensity gap can better reflect the different standard fortification intensities of the differences in seismic performance of buildings.