The historical earthquake activity is intense in the North China region. However, no middle-sized earthquakes have occurred in the last decades in the region since the Ms6.2 earthquake in the Zhangbei region in 1998. ...The historical earthquake activity is intense in the North China region. However, no middle-sized earthquakes have occurred in the last decades in the region since the Ms6.2 earthquake in the Zhangbei region in 1998. The quiescence of moderate and strong earthquakes is quite prominent in North China. In this paper, we use small earthquake records in 1970 ~ 2009 to study background seismic activity in the North China region. The spatial distributions of seismic parameters are presented, including b-value, the maximum magnitude and annual occurrence probability of earthquakes of M/〉6. 0. Our results show regions with low b-value that include the Yuncheng region in the Shanxi rift, the Suqian region located in the Tancheng-Lujiang fault zone and the Shijiazhuang region in the Taihangshan block. Our analysis on the synthetic spatial pattern of seismicity indicate that seismicity in the North China region is mainly affected by the regional dynamic factors of deep structures.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
基金supported by the International Scienceand Technology Cooperation Program of China(2010DFB20190)the"Basic Science Research Plan"of the Institute of Earthquake Science,China Earthquake Administration(Grant No.02092431)
文摘The historical earthquake activity is intense in the North China region. However, no middle-sized earthquakes have occurred in the last decades in the region since the Ms6.2 earthquake in the Zhangbei region in 1998. The quiescence of moderate and strong earthquakes is quite prominent in North China. In this paper, we use small earthquake records in 1970 ~ 2009 to study background seismic activity in the North China region. The spatial distributions of seismic parameters are presented, including b-value, the maximum magnitude and annual occurrence probability of earthquakes of M/〉6. 0. Our results show regions with low b-value that include the Yuncheng region in the Shanxi rift, the Suqian region located in the Tancheng-Lujiang fault zone and the Shijiazhuang region in the Taihangshan block. Our analysis on the synthetic spatial pattern of seismicity indicate that seismicity in the North China region is mainly affected by the regional dynamic factors of deep structures.
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.
