Articles in press have been peer-reviewed and accepted, which are not yet assigned to volumes /issues, but are citable by Digital Object Identifier (DOI).
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Design on high-precision time-synchronization system for distributed seismic data acquisition
Li Caihua, Teng Yuntian, Zhou Jianchao, Hu Xingxing, Wang Xizhen, Li Xiaojun, Wang Yushi
 doi: 10.11939/jass.20210124
[Abstract](62) [FullText HTML](21) [PDF 1803KB](15)
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In order to solve the time-synchronization problem of distributed seismic data acquisition system, we designed a new high-precision time-synchronization technical system in this paper. In this system, a synchronous timing pulse was transmitted periodically during data communication. Through transmitting time measurement and its transmission delay time correction of synchronous timing pulse, high-precision multi-channel time synchronization was achieved in this technical system. And a time-synchronization technical system designed with high-speed programed chips was used to carry out the time-synchronous test. The result proves that the synchronous timing accuracy of time-synchronous system is better than 200 ns when the optical fiber is 2 km, which indicates that the time-synchronization system is stable and practical.
Comparative study on two kinds of electrode grounding resistance measurement methods in geo-resistivity observation
Zhang Yu, Wang Lanwei, Hu Zhe
 doi: 10.11939/jass.20210151
[Abstract](491) [FullText HTML](71) [PDF 1914KB](37)
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When using the traditional three-pole method to measure the underground electrode grounding resistance, there will be a large measurement error, which suggests that the method will not be suitable for the underground electrode grounding resistance measurement. In view of this problem, this paper proposes a new method for measuring the electrode grounding resistance by using the geo-electric resistivity observation system, which is so called direct measurement method. And then, the grounding resistances of the underground observation power supply electrodes of Pinggu seismic station in Beijing were measured by using the traditional three-pole method and the direct measurement method. The measurement results show that, compared with the traditional three-pole method, the direct measurement method can get more reliable measurement results with less error, and can save human and material resources and measuring time.
Seismic waveforms and their signal-to-noise ratios of borehole observation in Donghai station,Jiangsu Province
Xu Jiren, Li Haibing, Zeng Xiangzhi, Zhao Zhixin
 doi: 10.11939/jass.20220195
[Abstract](73) [FullText HTML](27) [PDF 4225KB](22)
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The Jiangsu Donghai Crustal Activity in Continental Deep Hole National Observation and Research Station (Donghai station for short) is the first deep borehole seismic observation station in China. In order to explore an effective way to observe seismic information with high signal-to-noise ratio in high noise interference areas and to carry out the study on the borehole seismology, this paper analyzed the waveform characteristics and signal-to-noise ratios of waveforms recorded by a seismometer on the ground and three borehole seismometers at different depths underground in Donghai station. The results show that the waveform of a ML0.8 local event cannot be recognized on the seismogram of the seismograph on the ground due to the strong non-seismic noise disturbance around the Donghai station. However, the waveforms of the ML0.8 event can clearly be recognized on the seismograms of the three deep borehole seismographs. Furthermore, the earthquakes with zero magnitude or weaker negative magnitude recorded by the deep borehole seismographs are also more than those recorded by the seismograph on the ground. Meanwhile, the signal-to-noise ratios of waveforms recorded by borehole seismometers at three different depths are much higher than those recorded by the seismometer on the ground; moreover, the average signal-to-noise ratios of waveforms increase with the depths of observation instruments in the borehole. The average signal-to-noise ratio of the waveforms recorded by the seismograph at 1 559.5 m depth underground is 69.20 dB, and that of the seismograph at 2 545.5 m depth is 74.15 dB. Both of the two ratios reached the signal-to-noise ratio value of high fidelity waveform. Therefore, the observation data of seismograph at about 1 500 m depth can effectively avoid the interference on ground and record waveform with high signal-to-noise ratio. Such waveforms provide real and reliable data for the study on source process and site effect, promoting the development of deep borehole seismology.
Crustal thickness and vP/vS ratio of Arxan volcanic group in Xing’an-Mongolia orogenic belt
Zhang Yaxi, Wu Qingju, Zhang Ruiqing, Bai Lanshu
 doi: 10.11939/jass.20210070
[Abstract](77) [FullText HTML](31) [PDF 2548KB](33)
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The Arxan volcanic group is one of the most important volcanic groups in the Quaternary in Northeast China. It is of great significance to obtain information of crustal structure and vP/vS ratios in this area for studying the physical properties of the crust and tectonic evolution beneath the volcanoes. Original waveform data came from temporary broadband seismic stations in the Arxan volcanic area. The crustal thickness and average vP/vS in the study area are obtained by the P-wave receiver function and H-κ stacking method. The results show that the crust thickness is thicker in the northwest and thinner in the southeast, ranging from 33.9 km to 37.9 km, with thinner crust near the volcanic belt. There is a positive correlation between crustal thickness and elevation. The vP/vS ratio ranges from 1.73 to 1.83. There are three high vP/vS ratio areas in the study area: Chaihe town-Mingshuihe town, the north of Yimin Doren and Tianchi town. The thin crust and high wave velocity ratio areas beneath Arxan volcanic region may be caused by the upwelling of mantle material and underplating of basaltic magma.
Estimating of crustal thickness and vP/vS ratio using receiver function,surface wave and gravity data
Ren Zhiyuan, Li Yonghua, Qiang Zhengyang, Shi Lei
 doi: 10.11939/jass.20210065
[Abstract](155) [FullText HTML](70) [PDF 4077KB](54)
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Crustal thickness H and vP/vS ratio are two basic parameters for deciphering the crustal structure. We present an improved technique to constrain crustal thickness, vP/vS ratio and average P-wave velocity by using receiver function, surface wave dispersion and gravity data. Synthetic tests show that the improved method not only can accurately estimate H and vP/vS ratio, but also can give a reliable determination of the average crustal vP. Field data from two stations of South China are analyzed by the improved method, and the results also show the feasibility of the new method in constraining crustal properties.
Anomaly edge enhancement and topographic correction technology of linear source 3D borehole-to-surface electrical method
Xiong Zhitao, Tang Xingong, Zhang Lianqun, Li Dandan, Yu Junhu
 doi: 10.11939/jass.20220074
[Abstract](23) [FullText HTML](19) [PDF 4122KB](2)
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Based on the finite element method of unstructured grid, the efficient forward modeling of the borehole-to-surface electrical method derived by the linear current source under the condition of the 3D complex geoelectric model was carried out. The effects on the effectiveness and accuracy of the borehole-to-surface electrical method imaging were discussed by obtaining the electric field response derivative to characterize the boundary range of the target body, and using the difference field topography correction technology to eliminate the topographic influence. And the comparison between the numerical solution and the analytical solution verifies the effectiveness of the algorithm in this paper. The model calculation results shows that the spatial position and direction of the roadway with water accumulation cause significant changes in the apparent resistivity, and the extreme value of the apparent resistivity change rate accurately and clearly indicates the boundary position of the roadway. The normalized total horizontal derivative of the electric potential greatly improves the ability of the borehole-to-surface electrical method to identify the complex boundary position of the target body. The influence of topography on the distribution of borehole-to-surface electrical field is also serious, and its apparent resistivity response is approximately symmetrical to the shape of the topography. The difference field technique can effectively weaken the influence of topography on the high-precision imaging of the borehole-to-surface electrical method. The research results have important theoretical and practical significance for improving the data interpretation level and application effect of the borehole-to-surface electrical method.
Global sensitivity analysis of the generalized Pareto distribution model for seismicity in the northeast Tibetan
Ren Mengyi, Liu Zhe
 doi: 10.11939/jass.20210112
[Abstract](42) [FullText HTML](10) [PDF 2885KB](13)
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Because the selected values of input parameters of generalized Pareto distribution (GPD) model are difficult to avoid uncertainty, the input parameters uncertainty of this model may lead to uncertainty in the seismic hazard estimation. In this paper, we selected northeastern Tibetan Plateau as the case studied area, and proposed an uncertainty analysis process and method of seismic hazard estimation based on the global sensitivity analysis. First, we used the GPD seismicity model to obtain the results of seismic hazard estimation. And then, we selected starting time of earthquake catalog and magnitude threshold to be the input parameters of seismicity model. The E-FAST method with global sensitivity analysis function was used to quantitatively analyze the influence of the uncertainties of the two parameters and the interaction between the two parameters on the uncertainty of seismic hazard estimation. The results show that the seismic hazard estimation of the GPD model is more sensitive to the magnitude threshold. With different return periods, the sensitivity degree of seismic hazard estimation to magnitude threshold is different. For different return periods, there are nonlinear effects between the two input parameters on the uncertainty of seismic hazard estimation, and the degree of nonlinear effects is different. The uncertainty analysis process and method proposed in this paper can be applied to the uncertainty analysis of seismic hazard estimation based on other seismicity models.
Application of generalized extreme value distribution based on profile likelihood estimation in long term earthquake prediction
Zhao Yibin, Zhang Yanfang, Wang Fuchang, Ren Qingqing
 doi: 10.11939/jass.20210067
[Abstract](41) [FullText HTML](8) [PDF 2706KB](10)
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To describe the uncertainty of strong earthquake prediction, we introduced the profile likelihood estimation into parameter estimation of extreme value model for earthquake prediction. It elaborated the profile likelihood estimation principle and numerical algorithm of shape parameters and earthquake return level in generalized extreme value distribution. Meanwhile, a model of generalized extreme value distribution was created and was used to analyze the seismic risk of the East Kunlun seismic belt. The results showed that profile likelihood estimation and maximum likelihood estimation generated basically the same effect in point estimation of shape parameters and return level as well sd the estimation of confidence interval of earthquake return level within 10 years. However, in the confidence interval estimation of moderate and long interval earthquake return level, the asymmetric confidence interval of return level obtained through the profile likelihood estimation can more accurately express the uncertainty of predicted magnitude of a strong earthquake and more effectively predict the outcome.
Study on shallow S-wave velocity structure in Chongqing area
Dong lei, Shen Xuzhang, Chen Lijuan
 doi: 10.11939/jass.20210113
[Abstract](44) [FullText HTML](19) [PDF 4978KB](17)
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Based on the teleseismic waveform data recorded at permanent stations in Chongqing and its adjacent area from January 2011 to October 2018, the shallow S-wave velocity structure beneath the stations of Chongqing and its surrounding area is calculated by the method to constrain shallow structure based on direct P-wave amplitude in receiver functions. The results indicated that, the velocity structure of shallow S-wave in Chongqing is obviously related to the basin mountain structure, the low velocity anomaly in the basin corresponds to the characteristics of sedimentary layer, and the Daba mountain and Dalou mountain regions show relatively high velocity anomalies. The S-wave velocity of Huayingshan fault is higher than that of sedimentary layers on both sides of the fault, implying that the sedimentary layers in Sichuan basin are thin in the middle and thick on both sides. The Dianjiang MS4.4 earthquake and the Shizhu MS4.5 earthquake located in the east Sichuan detachment structure area are related to the obvious low velocity anomaly. The Rongchang MS4.7 and MS4.8 earthquakes have no obvious characteristics of high or low velocities, which may be related to water injection. The Wulong MS5.0 earthquake occurred on the high velocity body side that is conducive to strain accumulation of the high and low velocity junction. Finally, we discussed the seismogenic environment of five earthquakes in Chongqing since 2010.
Rupture process of the MS6.9 Menyuan,Qinghai, earthquake on January 8, 2022
Dai Danqing, Yang Zhigao, Sun li
 doi: 10.11939/jass.20220032
[Abstract](80) [FullText HTML](31) [PDF 3242KB](30)
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Based on the waveform data observed by the near field strong-motion stations, the earthquake rupture process can be quickly and stably inverted. This paper collected waveform data recorded by the strong-motion stations reconstructed in Qinghai during the implementation of the National Rapid Intensity Report and Seismic Early Warning Project. Based on these data, the rupture process of the Qinghai MS6.9 earthquake on January 8, 2022 was inverted by the iterative deconvolution and stacking method (IDS). The rupture model from inversion show that the rupture extends from the initial rupture point to a unilateral rupture in the southeast-east direction, with a duration of about 14 seconds (mainly focus on 2−8 seconds), a maximum slip of 3.6m, and a rupture length of about 20 km. The rupture extends longitudinally from the deep to the shallow, which is consistent with the surface rupture found in the field investigation. The spatial distribution of aftershock sequences shows significant segmentation characteristics, indicating complex tectonic transitions in the rupture zone. There is still the possibility of strong earthquakes in this area in the future.
Conjugate earthquake and measurement of friction coefficient in crustal medium
Wang Anjian, Chen Yuntai
 doi: 10.11939/jass.20210111
[Abstract](27) [FullText HTML](17) [PDF 14527KB](14)
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Anderson’s theory indicates that the conjugate rupture phenomenon of earthquake can be explained by Coulomb’s criterion, and there is a simple quantitative relationship between the angle of fault plane and the friction coefficient of underground rock. Based on the author’s method of calculating the friction coefficient of the medium through conjugate earthquakes, this paper systematically analyzes 19 domestic and foreign earthquakes with “X”-shaped or incomplete “X”-shaped (“L”-shaped) conjugate rupture characteristics. Analyze and compare with the source mechanism, regional stress axis direction and other data to determine the conjugate fault plane, and then determine the angle of the conjugate plane and calculate the internal friction coefficient of the rock. The research results further confirm that the conjugate fracture of natural earthquakes is in good agreement with the laboratory rock fracture, and the Coulomb criterion and Anderson theory are also valid at large scales. It is shown that the internal friction of the underground medium is determined by the conjugate angle. The coefficient is a useful supplement to the cognition of the characteristics of the underground medium.
A new method for expressing seismic hazards
Zhang Meng, Pan Hua
 doi: 10.11939/jass.20210106
[Abstract](72) [FullText HTML](30) [PDF 2142KB](22)
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The aim is to find a way to express seismic hazard with high accuracy, a wide range of exceedance probabilities and a convenient application. We reviewed several commonly used methods for seismic hazard expression, and the "characteristic coefficient method" based on a new function fitting the seismic hazard curve is proposed. The results show that the new function could effectively fit the seismic hazard curve, with a significant improvement compared to the extreme value function, and can adequately express the seismic hazard of a site. In addition, it is found that the parameter k (referred to as the characteristic coefficient in the paper), which characterizes the shape of the curve in this function, is related to the seismic environment faced by the site, that is, the hazard contribution for sites of low values of k essentially coming from the near field, while the contribution of sites for high values of k from long distances cannot be ignored.
Rupture process of the January 2022 Menyuan,Qinghai MS6.9 earthquake revealed by inversion of regional broadband seismograms
Zhu Yinjie, Luo Yan, Zhao Li
 doi: 10.11939/jass.20220148
[Abstract](114) [FullText HTML](41) [PDF 4789KB](39)
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Based on regional broadband waveform records, we investigate the rupture process of the January 2022 Menyuan MS6.9 earthquake by using the finite fault inversion method, and then combined with the geological knowledge and aftershock relocation results to determine the actual rupture fault., The inversion results show that the Menyuan earthquake occurred on a WNW-trending strike-slip fault. The rupture mainly occurred on both sides of the hypocenter, with a bilateral rupture characteristic. The maximum ruptures on the two sides of the hypocenter occurred at 2 s and 9 s. In terms of rupture scale, the depth of obvious rupture and the length of surface rupture are about 16 km and 20 km, and the maximum slip of 1.5 m occurs at about 6km. The seismic energy is mainly released in the first 15 s. The total seismic moment released is 1.23×1019 N·m, equivalent to MW6.67. The dip angle of the seismogenic fault plane is 84.6°, almost vertical. Due to the large range of rupture, the surface projection of obvious rupture is up to 34 km.
An estimation model of high frequency attenuation coefficient of ground motion for local site
Lang Ziping, Yu Ruifang, Xiao Liang, Fu Lei, Zhou Jian
 doi: 10.11939/jass.20220053
[Abstract](99) [FullText HTML](36) [PDF 2205KB](27)
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When using the stochastic finite fault method for ground motion simulation, how to select reasonable parameters to describe the near-surface high-frequency attenuation characteristics of a specific local site has important practical significance for evaluating the correctness of ground motion simulation results. In the prediction of ground motion parameters of engineering sites, how to quickly determine the value of this parameter is an urgent problem to be solved in practical applications. Firstly, the correlation that between the high-frequency attenuation coefficient κ0 of the site and the average shear wave velocity vS30 was analyzed; Then, based on the 546 κ0 coefficients calculated by domestic and foreign scholars, the root mean square value of κ0 in a certain time window was used to discuss its variation trend with the increase of the average shear wave velocity vS30.The results showed that although κ0 had obvious regional differences, its root mean square value showed a decreasing trend with the increase of vS30In order to obtain a reasonable κ0 estimation model, the linear function, polynomial function, logarithmic linear function and log-log linear function were used to preliminarily fit the relationship between the root mean square value of κ0 and vS30. The results show that the logarithmic linear function can be better describe the relationship between κ0 and vS30. Finally, based on the 477 data obtained from the screening, the model parameters were fitted by the least square method, and a practical model of κ0- vS30 suitable for engineering applications was obtained. The analysis of the applicability of the model shows that the κ0 estimation model constructed in this study can reasonably estimate the high-frequency attenuation of ground motion when predicting site ground motion parameters.
Joint inversion of multi-station receiver functions and gravity data for imaging Moho variations and average crustal vP/vS ratios
Hao Aowei, Zhang Haijiang, Han Shoucheng, Gao Lei
 doi: 10.11939/jass.20210179
[Abstract](222) [FullText HTML](80) [PDF 2149KB](58)
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Crustal thickness and vP/vS ratio are two important parameters for understanding crustal structure and composition, which can help to study regional tectonics. Receiver function analysis has been widely used for determining crustal thickness and vP/vS ratio by the H-κ method or the H-κ-c method. However, it can only acquire average crustal thickness and vP/vS ratio below each seismic station, but cannot constrain their lateral variations among seisimic stations due to their sparse and irregular distribution. On the other hand, the gravity data has been widely used to derive the Moho variaitons, which has a good coverage and resolution laterally but poor resolution vertically. Therefore, in this study we have developed a new joint inversion method of receiver functions and gravity data to simultaneously invert for variations of Moho depths and average crustal vP/vS ratios in a region. The method takes advantage of complementary strengths of receiver functions and gravity data, and can simultaneously fit all receiver functions and gravity data in the region. The synthetic tests show that the proposed joint inversion method produces more reliable results than only receiver function analysis, especially for the crustal thickness.
A transfer function based on Laplace transform to improve the accuracy of narrow-frequency velocity recording
Sun Yixuan, Xu Guolin
 doi: 10.11939/jass.20210182
[Abstract](74) [FullText HTML](36) [PDF 3412KB](13)
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Affected by the flat response range of the narrow-band seismograph, the narrow-band recording has the problem of low-frequency component distortion, which limits the usable range of the seismic recording. To solve this problem, the authors deduce an improved transfer function based on the Laplace transform and bilinear transform to realize the correction from narrow-band seismic records to broadband seismic records. The Japanese Hi-net velocity records are used as an example for correction, and the corrected velocity records are compared with the same KiK-net acceleration integral velocity records. The results show that the original velocity records are distorted at low frequencies, while the corrected waveform is consistent with the KiK-net acceleration integral velocity records. The analysis shows that the improved transfer function can effectively solve the distortion of the low-frequency components in the original velocity records, which effectively widens the usable range of low-frequency. Compared with the N.Nakat-corrected velocity recording method, the velocity recording corrected with the transfer function given in this paper is more accurate in terms of amplitude and waveform.
3-D P and S wave velocity and Poisson’s ratio structures and seismic activity in Shandong area
Fan Jianke, Ding Zhifeng, Guo Huili, Su Daolei, Zhang Bin
 doi: 10.11939/jass.20210077
[Abstract](138) [FullText HTML](69) [PDF 5105KB](37)
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Shandong area is located in eastern China, where faults develop and earthquakes occur frequently. Therefore, high resolution velocity structure is quite necessary for better understanding causal mechanism of earthquakes. Based on abundant P and S wave arrival times recorded at stations in and around Shandong area, high resolution 3-D P wave velocity (vP), S wave velocity (vS) and Poisson’s ratio structures are obtained. The results reveal that, the hypocenter of the 2020 Changqing (M4.1) earthquake is located in the transition zone where seismic velocity and Poisson’s ratio change drastically in the horizontal direction. This suggests that the 2020 Changqing (M4.1) earthquake may be caused by the sinistral strike-slip movement of the Changqing fault affected by the regional stress field. Occurrence of the 2003 Laoshan (M4.1) earthquake and Laoshan, Rushan and Changdao earthquake swarms may be strongly affected by fluids. These fluids invaded along pre-existing faults or cracks in relatively intact rock bodies, and induced faults to act or cracks to break up, which caused the occurrence of middle and strong earthquakes and earthquake swarms.
The characteristics of subway stray current on geo-electrical resistivity observation
Wang Lanwei, Zhang Yu, Zhang Xingguo, Hu Zhe
 doi: 10.11939/jass.20210197
[Abstract](634) [FullText HTML](44) [PDF 17111KB](26)
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The geo-electrical resistivity observation is one of the most important methods in the study of earthquake precursor, and the characteristics of the stray current during subway operation in the geo- resistivity observation are useful for analyzing the geoelectric observation data and the anomaly variation before earthquake. Based on the study on the generation mechanism, the quantitatively results of the influence of stray current on geo-electrical resistivity observation were given in this paper. The result shows that the effect distance can reach dozens or even to a hundred kilometers. Through monitoring the stray current in some geo-electrical resistivity observation stations around cities, such as Beijing Tongzhou station, Tianjin Qingguang, Baodi and Tanggu stations, Jiangsu Jiangning station and Liaoning Xinchengzi station, the amplitude and frequency range of the stray current signal as well as its spatial distribution characteristics were analyzed. It shows that the amplitude of the signal ranges from several to tens millivolt, and the period range is mainly from 50 s to 200 s. Due to the influence of stray current, the signal-to-noise ratio is decreased by 10 to 30 dB, and the accuracy of the observation data is more than 20 times worse than the specified requirement. According to the characteristics of the stray current propagation, several methods which can be used to suppress the signal were proposed in this paper, and it will provide a foundation for the identification of anomaly information from the observation data and anti-interference technology study.
Shallow velocity structure and seismogenic environment in the Zigui section of the Three Gorges Reservoir region of China
Hu Jintao, Xie Jun, Wei Zigen, Jin Chao
 doi: 10.11939/jass.20210194
[Abstract](221) [FullText HTML](48) [PDF 3065KB](56)
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After the impoundment of the Three Gorges Reservoir in 2003, shallow earthquakes occurred frequently, which had a great impact on local productions and lives. The study of shallow velocity structure is of great significance for shallow seismic disaster assessment and disaster prevention and reduction in Zigui area. In this paper, based on the vertical component continuous waveform records of 24 mobile seismic stations in Zigui area from June to July of 2020, the empirical Green’s functions between stations are obtained by cross-correlating of the ambient seismic noise, the Rayleigh wave group velocity dispersion curves of 0.6−5 s are extracted, and the inversion for the three-dimensional S-wave velocity model is obtained within 6 km near the surface of the region. The results show that the S-wave velocity of Zigui basin and its south adjacent area is significantly lower than that of the eastern fault area, which is consistent with the structural evolution and sedimentary characteristics of different structural blocks in the studied area; an earthquake with MS4.2 occurred on the vertical high-velocity and low-velocity junction area of the study area in 2014. The S-wave velocity decreases obviously near the Yangtze River region in the fault zone, indicating that the Yangtze River water penetrates into the fault area. Therefore, the frequent occurrence of earthquakes in Zigui area is related to the water load and water infiltration of the Three Gorges reservoir.
Applicability of the Next Generation Attenuation-West2 ground-motion model to the components of near-fault velocity pulse-like ground motions
Zhao Xiaofen, Wen Zengping, Xie Junju, Xie Quancai
 doi: 10.11939/jass.20210176
[Abstract](296) [FullText HTML](95) [PDF 9564KB](79)
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The traditional ground-motion models (GMMs) do not account for pulse effects and may therefore fail to estimate seismic hazards and risk at near-fault sites, where pulse-like ground motions are expected. Thus, the applicability of the newest generation NGA-West2 GMMs to the near-fault velocity pulse-like ground motions need to be tested. The near-fault strong ground motions are quantitatively identified by considering the uncertainty of pulse orientation and using wavelet method from recent earthquake since 2013 to form a new pulse database. Based on the new pulse database, long-period pulses are extracted from the original pulse records by using wavelet method. Based on a quantitative analysis of the epsilon parameter, we quantitatively test the applicability of the NGA-West2 ground-motion model to the near-fault velocity pulse-like ground motions. The results show that the four NGA-West2 models are more suitable for describing the residual recordings at the studied period, but underestimate the pulse original ground motions especially around the pulse period. We noted that, during the four NGA-West2 models, the applicability of the CB2018 to the residual ground motions is the best. This study provides an excellent opportunity to quantitatively evaluate the NGA-West2 GMMs and to update these models in the near future, and also provides a basis for incorporating pulse effects into near-fault probabilistic seismic hazard analysis and seismic design.
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2022, 44(5).  
[Abstract](72) [PDF 1093KB](19)
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2022, 44(5): 733-733.  
[Abstract](138) [FullText HTML](80) [PDF 668KB](73)
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Discussion
Some thoughts on earthquake resistance and disaster prevention
Zhang Minzheng
2022, 44(5): 733-742.   doi: 10.11939/jass.20220088
[Abstract](588) [FullText HTML](194) [PDF 1231KB](233)
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This paper attempts to discuss several issues in China’s earthquake engineering researches and disaster reduction undertakings based on a philosophical and scientific points of view. The paper points out that the seismic intensity by macroscopic investigation does not have the exact connotation and extension of scientific concepts, it is impossible to verify the results risk analysis, the adoption of seismic fortification standards fundamentally depends on the development level of social economy and technology, the research of fault avoidance has not yet reached the stage of engineering application, the exact results of numerical simulation of structural seismic response cannot be pursued. Finally, some of suggestions and prospects for seismic engineering researches are proposed.
Review
Risk-targeted seismic zoning maps
Pan Hua, Zhang Meng
2022, 44(5): 743-751.   doi: 10.11939/jass.20220161
[Abstract](221) [FullText HTML](154) [PDF 2112KB](126)
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To ensure the consistency of building collapse risk within the country, a risk-targeted seismic zoning map is proposed. The risk integral method calculates the target risk by the convolution of the seismic hazard curve and the structural vulnerability curve. Currently, the use of risk-targeted seismic zoning maps has been widely used in practice in the United States, and related studies have been conducted in France, Romania, Canada, Indonesia, Europe and China. This article introduces the basic principles of using the risk integral method to determine the risk-targeted ground motion parameters and reviews the recent progress of research and application of this technique in China and abroad. In addition, we discuss the future development of risk-targeted seismic zoning maps and some of the problems may face.
Review on the commonly-used ground motion parameters attenuation relationships for shallow crustal earthquakes in Chinese mainland
Xiao Liang, Yu Yanxiang
2022, 44(5): 752-764.   doi: 10.11939/jass.20220142
[Abstract](194) [FullText HTML](125) [PDF 1590KB](139)
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This paper illustrates the key points of ground motion parameters, earthquake parameters, base models and regression methods, which are always involved in applying attenuation relationships of ground motion parameters. These parameters and models could satisfy the demands for earthquake engineering application in Chinese mainland. Taking North China as an example, this paper reviews the major features of several commonly-used attenuation relationships for shallow crustal earthquakes in recent decades, and their differences are compared and analyzed. Finally, the authors summarize the limitations of current researches on attenuation relationships in Chinese mainland, and propose the research prospect for future study.
Review on issues of near-fault velocity pulse-like ground motions
Zhao Xiaofen, Wen Zengping
2022, 44(5): 765-782.   doi: 10.11939/jass.20220141
[Abstract](237) [FullText HTML](150) [PDF 2366KB](127)
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The study of near-fault velocity pulse-like ground motions is of great value to revealits damage mechanism, seismic fortification, and seismic design in the near-fault region. In this paper, the formation mechanisms of the pulse are summarized. The idea of distinguishing the pulses caused by the forward directivity effects and fling effects is discussed. Secondly, the identification methods of near-fault velocity pulses are systematically introduced and their advantages and disadvantages are reviewed. In addition, based on the characteristics of the pulse, the influence of the forward directivity effect on the pulse characteristics and the amplification effects of pulses on response spectra are discussed. Finally, the ground motion input and influence of pulses on structures are summarized. And the key questions of the pulse ground motion input are discussed. In the future, the research work of velocity pulse ground motion should be fully integrated with the actual engineering needs, and the standardization of theoretical results and engineering practice should be promoted.
Review on research of ground motion site adjustment coefficient
Yan Jingru, Zhang Yushan, Kan Wenliang
2022, 44(5): 783-796.   doi: 10.11939/jass.20220086
[Abstract](192) [FullText HTML](125) [PDF 2207KB](114)
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This paper reviews and summarizes the main research results on the adjustment coefficients of ground motion field at home and abroad over the past 20 years, focusing on the effective means of considering the influence of filed conditions on ground motion parameters through strong ground motion observation and numerical theory methods. It summarizes the applicability along with the pros and cons of various methods, conducts a comparative analysis of the main results at home and abroad by combining relevant codes and provisions, and concludes that the coefficients of soft soil field in China are smaller than the international level. What’s more, the reasons for this difference are further analyzed. Finally, based on the current development trend of international seismic zoning work and the new technical requirements of the relevant codes in various industries, it puts forward prospects for the research work of the new generation of zoning maps.
Advances in ground motion attenuation relationship of Chinese mainland
Liu Ping, Xu Zhengwei, Luo Qifeng
2022, 44(5): 797-809.   doi: 10.11939/jass.20220117
[Abstract](269) [FullText HTML](136) [PDF 1620KB](135)
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Ground motion attenuation relationship is one of the primary methods for site ground motion estimation. In this paper, firstly, the development of the ground motion attenuation relationship equations is briefly described. Then it analyzes the importance of the conversion method proposed by Mr. Hu Yuxian, reviews the development process of the attenuation relationship in the Chinese mainland, and focuses on research progress of horizontal ground motion, vertical ground motion, and other ground motion parameters. Finally, the limitations existing in the study of attenuation relationships are discussed, and suggestions for developing the strong ground motion database and the attenuation relationship in regions with poor ground motion records are put forward.
Research Paper
An efficient seismic response spectrum method under multi-support excitations
Wang Junjie, Guo Jin
2022, 44(5): 810-823.   doi: 10.11939/jass.20220093
[Abstract](179) [FullText HTML](102) [PDF 2351KB](87)
Abstract:
The seismic response spectrum analysis of structures is time-consuming under multi-support excitations. The seismic spectral response of structures can be expressed based on several correlation coefficients and the time consumption can be greatly reduced if the coefficients are expressed in closed-form. In this paper, approximate expressions of spatial coherence functions are suggested. Then integrals for the coefficients are carried out analytically and their closed-form expressions are obtained. The closed-form expressions are developed from Clough-Penzien’s auto-power spectral density and Hu’s APSD. The numerical results show that the approximate closed-form expressions of correlation coefficients are of enough engineering accuracy and high efficiency for response spectrum method under multi-support excitations.
Characteristics of pulses in near-fault ground motion based on Hilbert-Huang transform
Wang Dongsheng, Chen Xiaoyu, Zhang Rui, Guo Wei
2022, 44(5): 824-844.   doi: 10.11939/jass.20220090
[Abstract](177) [FullText HTML](107) [PDF 3735KB](111)
Abstract:
Large-amplitude and long-period pulses are observed in velocity time histories of near-fault ground-motion records. The pulses in these records can pose severe ductility or strength demands to the near-fault structures and can subject them to higher collapse risks. Further research on the characteristics of pulses in near-fault ground motion is beneficial to deepen the understanding of the response of structures close to faults, and provide theoretical basis for the aseismic design. At present, methods related to strong motion processing and identification of near-fault pulses mainly focus on the single pulse in a record, so the multi-pulse characteristics of near-fault ground motions are less involved. Hence, a set of methods based on Hilbert-Huang transform (HHT) are proposed here to investigate the multi-pulse characteristics. Firstly, the raw near-fault record is corrected by the proposed HSA method, and then the ideal pulse signal can be extracted by the HHT method from the corrected record. According to the extracted pulse signal, the statistical relationships between pulse parameters and earthquake parameters are investigated. Finally, an effective strong motion duration is defined based on the pulse duration, which is verified by the nonlinear time history analysis of multi-storey buildings. The developed methods are particularly suitable for multi-pulse records. Stable peak ground displacement (PGD) and physically baseline offset time history can be obtained by the HSA method. Each velocity pulse in a record can be located in the time domain exactly and automatically by the HHT method. The proposed definition of strong motion duration for near-fault records can well characterize the intensity of multi-pulse records.
Estimation of average displacement of fault surface co-seismic dislocations
Wang Long, Liu Aiwen, Li Xiangxiu, Fan Xiaoqing, Zhang Libao, Wang Yu
2022, 44(5): 845-852.   doi: 10.11939/jass.20220122
[Abstract](195) [FullText HTML](104) [PDF 1601KB](103)
Abstract:
According to the concept of pipeline performance design, the current seismic code for oil and gas pipelines stipulates that the displacement of fortified faults in important sections and general sections are the predicted maximum displacement and average displacement, respectively. However, at present, the fault displacement estimation method generally gives only the maximum displacement of the fault in the next 100 years, but not the average displacement. Therefore, based on the investigation results of co-seismic dislocation distribution of seismogenic faults on the surface at home and abroad, the distribution characteristics of co-seismic dislocations along the surface fracture trend of the fault are summarized and analyzed in this paper. And then the ratio of the average co-seismic dislocation of the fault to the maximum co-seismic dislocation of the fault is summarized by the statistical comparison and analysis of the average displacement obtained by different calculation methods in the actual earthquake cases. Anyway, based on a large number of data of seismic fault displacement at home and abroad, considering a certain safety factor, this paper suggests that 2/3 of the maximum displacement of the predicted fault should be used as the fortification displacement of the oil and gas pipeline in general sections.
Ground motion prediction of MW≥7.5 on Xiadian fault
Zhou Hong, Wang Wenjing
2022, 44(5): 853-867.   doi: 10.11939/jass.20220089
[Abstract](235) [FullText HTML](135) [PDF 8478KB](115)
Abstract:
The prediction of ground motion fields for potential earthquakes is important for urban planning and regional seismic hazard assessment. In this paper, the prediction of MW≥7.5 ground motion is carried out for the Xiadian fault. Firstly, the earthquake source is set based on the full rupture patterns to cover the unknown information of the Xiadian fault as much as possible. Then the ground motion field in the study area is simulated due to the MW≥7.5 earthquake on the Xiadian fault. Furthermore, the spatial distribution of ground motion at each site is filtered based on the quantile method, and the distribution characteristics of peak ground acceleration and peak ground velocity for the inclusion of uncertain sources are discussed. The results show that an MW7.9 earthquake on the Xiadian fault will produce the strong ground motion in Tongzhou district and Beijing center zone. After that, the spatial distribution of the ground motion due to the MW7.5 earthquake from the simulated source is discussed. The results illustrate that the simulated ground motion from the two types of sources can corroborate each other for the same magnitude. Our study provides a method for the earthquake hazard predictions due to the potential sources with some unknowns.
A new exploration of the risk assessment method of earthquake disasters in urban agglomerations:Taking the Guangdong-Hong Kong-Macao Greater Bay Area as an example
Jiang Hui, Guo Endong, Lin Xuchuan, Liu Zhi, Lu Banghua, Liu Aiwen, Zhang Yi
2022, 44(5): 868-880.   doi: 10.11939/jass.20220096
[Abstract](282) [FullText HTML](132) [PDF 8157KB](113)
Abstract:
Based on the preliminary research results of earthquake disaster risk assessment in the Guangdong-Hong Kong-Macao Greater Bay Area, the earthquake environment, distribution of disaster-bearing bodies and site characteristics of urban agglomerations in the bay area are analyzed, and two scenario earthquake principles for determining the earthquake input are proposed, namely, setting earthquakes in potential source areas principle and maximum risk setting seismic principle, which can make risk assessment of earthquake disasters in urban agglomerations more accurate. On the basis of previous studies, the expression of earthquake disaster risk considering the influence of site conditions is proposed. The disaster risk assessment method of buildings and lifeline engineering suitable for 3D simulation of seismic input within non-uniform excitation is explored, and the idea of considering the influence of site in the disaster risk assessment of buildings and lifeline engineering is proposed. Some valuable suggestions are put forward to objectively evaluate the earthquake disaster and loss risk of urban agglomeration.
Extraction of seismic damage information of buildings from three-dimensional images of oblique photography based on multi-scale segmentation and deep learning
Shuai Xianghua, Jing Shuaijun, Zheng Xiangxiang, Liu Qin
2022, 44(5): 881-890.   doi: 10.11939/jass.20220105
[Abstract](146) [FullText HTML](97) [PDF 7001KB](95)
Abstract:
The method of combining multi-scale segmentation and deep learning is used to extract the seismic damage information of buildings from three-dimensional images of oblique photography after an earthquake. In this way, the comprehensive damage information of the roof and wall of the building is obtained. Taking the 2017 MS7.0 Jiuzhaigou earthquake as an example, firstly, based on the three-dimensional image of the roof and wall of the building, the multi-scale segmentation of samples are divided into three categories: intact building surface, damaged building surface, other ground objects and background. Secondly, 211 sample set with 100×100 pixel are selected to train the neural convolutional network model. The trained model is used to extract the seismic damage information of buildings in Qianguqing scenic spot and Zhangzha primary school. Finally, the accuracy of the extracted results is compared with the visual interpretation results. The results show that the extraction accuracy of damaged building surface is 65.5% and 71.1% respectively, the overall classification accuracy is 82.1% and 84.1% respectively, and the Kappa coefficient is 68.7% and 64.9% respectively. The result indicates that this method has certain advantages in seismic damage extraction of buildings from three-dimensional images of oblique photography.
Effect of pulse characteristics of near-fault ground motions on the response of equipment-structure coupled isolation system
Han Miao, Jiang Jinwei, Du Hongkai, Zhao Minghe
2022, 44(5): 891-902.   doi: 10.11939/jass.20220129
[Abstract](196) [FullText HTML](82) [PDF 3296KB](89)
Abstract:
Based on the model of equipment-structure coupled isolation system, 50 near-fault pulse-like seismic waves were selected and the effect of period ratio TP/T (the ratio of the pulse period to the basic period of the structure) and pulse energy on the structural response was analyzed using TP/T=1 as the dividing line; and the relationships between the displacement ratio of isolation layer and the period ratio and pulse energy were fitted while the zero-crossing times is not less than 5. The analyses show that the influence of pulse characteristics on the structure is mainly related to the period ratio TP/T and the pulse energy, while the influence of the zero-crossing times of the acceleration curve corresponding to the velocity pulse needs to be considered. Furthermore, the equipment response is directly related to the top floor acceleration, but there is no significant direct correlation with the pulse characteristics of near-fault ground motions.
A shake table test for the rotation response of rigid bodies under seismic excitation
Zhao Shiwei, Luo Qifeng, Pan Kang, Zhai Yongmei, Lu Wensheng, Zhao Bin, Cao Wenqing
2022, 44(5): 903-910.   doi: 10.11939/jass.20220092
[Abstract](209) [FullText HTML](103) [PDF 2139KB](80)
Abstract:
In 2008 Wenchuan earthquake, an interesting torsion phenomenon attracts our attention: Most of the stone statues, which were placed upon the banisters of one zigzag bridge in Taibai Park, Jiangyou City, Sichuan Province, rotated an angle from their original location with little translation displacements. To simulate and further study this phenomenon, a group of stone statue models with different asymmetric characteristics were made, and then they were arranged in different location and direction on the shake table to do shake tests. The results show that: ① The torsional phenomena of the statue models appeared when input 3D accelerations from the shake table, and the acceleration amplitudes are 1.5 times of the original seismic records. Also, the phenomena were similar to those in the Taibai Park in Wenchuan earthquake. However, when the input accelerations were only in two horizontal directions, the torsional phenomena would not appear even when the amplitude was large enough. ② The torsional phenomena of the stone statue models showed different modes with different model asymmetric characteristics and different acceleration input angles. ③ The most significant factor that causes the torsional phenomena is the vertical seismic input. The statue rotation did not occur without it. So for this case, vertical ground motion is crucial and cannot be ignored.
Study on structural dynamic response under near fault ground motion with different time-frequency characteristics
Han Miao, Zhao Minghe, Du Hongkai, Jiang Jinwei
2022, 44(5): 911-919.   doi: 10.11939/jass.20220135
[Abstract](170) [FullText HTML](120) [PDF 2008KB](105)
Abstract:
The dynamic response of the anti-seismic structure and the seismic isolation structure Coupled equipment under the action of seismic waves with different time-frequency characteristics is studied, and the wavelet analysis of the test data of the five-layer steel frame shaking table model is carried out. The results show that: the dynamic response of the main structure is directly related to the time-frequency characteristics of seismic waves; due to the filtering effect of the main structure and seismic isolation bearings, the dynamic response of the equipment is significantly affected by the time-frequency characteristics of seismic waves, but there is no direct correlation; isolation can reduce the amplification coefficient of the equipment by moving the frequency of the device away from the frequency of the main structure; the variation trend of the acceleration of the main structure after coupling the equipment depends on the seismic wave energy distribution with different time-frequency characteristics.