Mountain tunnel crossing a normal fault in seismically active zone is easily affected by normal fault slip and earthquake. It is necessary to study tunnel dynamic response under action of normal fault slip and earthqu...Mountain tunnel crossing a normal fault in seismically active zone is easily affected by normal fault slip and earthquake. It is necessary to study tunnel dynamic response under action of normal fault slip and earthquake. In this paper, a three-dimensional normal fault sliding device was designed, and a shaking table test was carried out to study tunnel seismic performance under normal fault slip. The results show that peak acceleration of lining is dominated by an existence of fault and direction of seismic excitation, not normal fault slip. And the incremental strains of lining in critical zone with 1.7 times fault thickness and centered in faults induced by normal fault slip and seismic excitation are larger than ones only by seismic excitation. And the incremental strains in critical zone increase with the increase of normal fault slip magnitude ranging from 0 to 2 mm. And normal fault slip results in a significant reduction of overall tunnel stiffness subjected to an earthquake. These experimental results provide a scientific reference for prevention and control measurement of tunnel damage under earthquake and normal fault slip.展开更多
This paper reviews the history and progress of research on active tectonics in China and overseas.By giving a brief introduction on the history of active tectonic research in China and other countries,the paper sums u...This paper reviews the history and progress of research on active tectonics in China and overseas.By giving a brief introduction on the history of active tectonic research in China and other countries,the paper sums up the process and development of quantitative investigation of active tectonics since the 1980s.The focus is on the main efforts and progress made in China on certain aspects of research,such as basic surveys and applied investigation of active tectonics,the study of theories related to regional active tectonics and their kinematics and geodynamics,surveys on coupling relations between deep and shallow structures,active fault surveys and prospecting and seismic hazard assessment in urban areas,as well as the efforts made using Quaternary geochronology.Furthermore,the paper looks back on Chinese quantitative investigation of active tectonics in China and sums up cognitions derived from studies on the determination of several basic and measurable parameters of active tectonics.These parameters include the length of fault and fault segmentation,coseismic slip and cumulative slip,fault slip rate,the sequence of paleoearthquake events and the time elapsed since the most recent event.At the same time,efforts and progress made in China on assessing the long-term seismic potential for active faults and evaluating the risk from potential active fault movement have been reviewed by summarizing research on developing theories,models,methods and the application of time-dependent seismic potential to probabilistic assessment,magnitude estimation for potential earthquakes on active faults,and the forecast of potential risk caused by active fault movement.Finally,in consideration of the realities and problems in the research of active tectonics in China,the authors put forward several suggestions for issues worthy of more attention for further investigation in the future.展开更多
In this article,we use the CAP method to invert the focal mechanism of Xinyuan-Hejing M S6. 6 earthquake on June 30,2012. Our result shows that the best double couple solution of the M S6. 6 event is 299°,68°...In this article,we use the CAP method to invert the focal mechanism of Xinyuan-Hejing M S6. 6 earthquake on June 30,2012. Our result shows that the best double couple solution of the M S6. 6 event is 299°,68° and 164° for strike,dip and rake angles respectively. The other nodal plane is 35°,75° and 23°. The azimuth and dip angle of the P-axis are 166°and 5°,those of the T-axis are 258° and 26°. The moment magnitude is 6. 3. The estimated focal depth is about 21 km. The predominant rupture direction of this seismic sequence is NWW. The dip angles are between 60° and 90°. The rake angles are in the majority of ± 180°± 30°. The predominant strike of the azimuthal angle of the P-axis is near NS and T-axis is near EW. Preliminary analysis indicates that nodal plane I is the seismogenic fault,which is a NWW-trending,nearly upright left-lateral strike-slip fault.The displacement property,the principal compressive stress of this M S6. 6 earthquake and the P-axis preponderant orientation of this seismic sequence agree with the characteristics of the tectonic stress field of the focal area and its surroundings.展开更多
By taking moderate-strong earthquakes in South,North and West China as the research subjects and taking into consideration the fault strikes in these regions,this paper selects 8 kinds of seismology indexes with clear...By taking moderate-strong earthquakes in South,North and West China as the research subjects and taking into consideration the fault strikes in these regions,this paper selects 8 kinds of seismology indexes with clear physical significance and strong independence to carry out spatial scanning of the parallel,vertical and oblique slip of fault along the fault strike.Based on the size of correlation coefficients between the scanning curve and source region curve we quantitatively analyze the difference between scan results among different slip modes and study the impact of fault strike in different tectonic divisions on scanning results and variation rules of seismological parameters.The results show that not only does the change of spatial parameters have a great influence on seismological parameter scanning,but so does the fault strike in the source region.This paper presents the optimum condition parameters with least spatial influencing scanning scope for different magnitude seismology indexes and analyzes the possible influence of fault strike on seismological parameter scanning results.展开更多
The Kunming basin is a Cenozoic faulted basin controlled by N-S trending active faults. there are totally 8 main active faults in and around the Kunming basin area. Inversion of fault slip data suggests that the stres...The Kunming basin is a Cenozoic faulted basin controlled by N-S trending active faults. there are totally 8 main active faults in and around the Kunming basin area. Inversion of fault slip data suggests that the stress field of the Kunming basin has experienced two major stages. In the first stage ( from the late-Pliocene to mid-Pleistocene),the regional tectonic stress field was characterized by near E-W compression and near N-S extension. In the second stage (from the late-Pleistocene to the present),the tectonic stress field has been mainly characterized by NNW-SSE compression and NEE-SWW extension. Under such a stress field,the near N-S trending faults in the region mainly show a lateral slip.展开更多
基金Project(51674287)supported by the National Natural Science Foundation of China。
文摘Mountain tunnel crossing a normal fault in seismically active zone is easily affected by normal fault slip and earthquake. It is necessary to study tunnel dynamic response under action of normal fault slip and earthquake. In this paper, a three-dimensional normal fault sliding device was designed, and a shaking table test was carried out to study tunnel seismic performance under normal fault slip. The results show that peak acceleration of lining is dominated by an existence of fault and direction of seismic excitation, not normal fault slip. And the incremental strains of lining in critical zone with 1.7 times fault thickness and centered in faults induced by normal fault slip and seismic excitation are larger than ones only by seismic excitation. And the incremental strains in critical zone increase with the increase of normal fault slip magnitude ranging from 0 to 2 mm. And normal fault slip results in a significant reduction of overall tunnel stiffness subjected to an earthquake. These experimental results provide a scientific reference for prevention and control measurement of tunnel damage under earthquake and normal fault slip.
基金funded by the"Experimental Exploration of Active Faults in Urban Areas(20041138)"project of the National Development and Reform Commission of China
文摘This paper reviews the history and progress of research on active tectonics in China and overseas.By giving a brief introduction on the history of active tectonic research in China and other countries,the paper sums up the process and development of quantitative investigation of active tectonics since the 1980s.The focus is on the main efforts and progress made in China on certain aspects of research,such as basic surveys and applied investigation of active tectonics,the study of theories related to regional active tectonics and their kinematics and geodynamics,surveys on coupling relations between deep and shallow structures,active fault surveys and prospecting and seismic hazard assessment in urban areas,as well as the efforts made using Quaternary geochronology.Furthermore,the paper looks back on Chinese quantitative investigation of active tectonics in China and sums up cognitions derived from studies on the determination of several basic and measurable parameters of active tectonics.These parameters include the length of fault and fault segmentation,coseismic slip and cumulative slip,fault slip rate,the sequence of paleoearthquake events and the time elapsed since the most recent event.At the same time,efforts and progress made in China on assessing the long-term seismic potential for active faults and evaluating the risk from potential active fault movement have been reviewed by summarizing research on developing theories,models,methods and the application of time-dependent seismic potential to probabilistic assessment,magnitude estimation for potential earthquakes on active faults,and the forecast of potential risk caused by active fault movement.Finally,in consideration of the realities and problems in the research of active tectonics in China,the authors put forward several suggestions for issues worthy of more attention for further investigation in the future.
基金jointly sponsored by Earthquake Science and Technology Spark Plan of China Earthquake Administration(XH13028Y)Special Program for Seismic Network Youth Backbone Training of China Earthquake Administration(20120105)
文摘In this article,we use the CAP method to invert the focal mechanism of Xinyuan-Hejing M S6. 6 earthquake on June 30,2012. Our result shows that the best double couple solution of the M S6. 6 event is 299°,68° and 164° for strike,dip and rake angles respectively. The other nodal plane is 35°,75° and 23°. The azimuth and dip angle of the P-axis are 166°and 5°,those of the T-axis are 258° and 26°. The moment magnitude is 6. 3. The estimated focal depth is about 21 km. The predominant rupture direction of this seismic sequence is NWW. The dip angles are between 60° and 90°. The rake angles are in the majority of ± 180°± 30°. The predominant strike of the azimuthal angle of the P-axis is near NS and T-axis is near EW. Preliminary analysis indicates that nodal plane I is the seismogenic fault,which is a NWW-trending,nearly upright left-lateral strike-slip fault.The displacement property,the principal compressive stress of this M S6. 6 earthquake and the P-axis preponderant orientation of this seismic sequence agree with the characteristics of the tectonic stress field of the focal area and its surroundings.
基金sponsored by sub-project ofNotional Key Technology R&D Program (2006BAC01B020105)the Key Technology R&D Program of AnhuiProvince (08010302204),China
文摘By taking moderate-strong earthquakes in South,North and West China as the research subjects and taking into consideration the fault strikes in these regions,this paper selects 8 kinds of seismology indexes with clear physical significance and strong independence to carry out spatial scanning of the parallel,vertical and oblique slip of fault along the fault strike.Based on the size of correlation coefficients between the scanning curve and source region curve we quantitatively analyze the difference between scan results among different slip modes and study the impact of fault strike in different tectonic divisions on scanning results and variation rules of seismological parameters.The results show that not only does the change of spatial parameters have a great influence on seismological parameter scanning,but so does the fault strike in the source region.This paper presents the optimum condition parameters with least spatial influencing scanning scope for different magnitude seismology indexes and analyzes the possible influence of fault strike on seismological parameter scanning results.
基金sponsored by the Basic ResearchSpecial Program for the Central Level of Scientific Research Institutes ( ZDJ2007-8 )the National Key Technology R&D Program (2006BAC13801),China
文摘The Kunming basin is a Cenozoic faulted basin controlled by N-S trending active faults. there are totally 8 main active faults in and around the Kunming basin area. Inversion of fault slip data suggests that the stress field of the Kunming basin has experienced two major stages. In the first stage ( from the late-Pliocene to mid-Pleistocene),the regional tectonic stress field was characterized by near E-W compression and near N-S extension. In the second stage (from the late-Pleistocene to the present),the tectonic stress field has been mainly characterized by NNW-SSE compression and NEE-SWW extension. Under such a stress field,the near N-S trending faults in the region mainly show a lateral slip.
