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
By analyzing higher-accuracy location data of the Tangshan earthquake sequence,a clear distribution pattern of three aftershock belts in the NE,NWW,and NW directions of has been obtained.The analysis reveals three rup...By analyzing higher-accuracy location data of the Tangshan earthquake sequence,a clear distribution pattern of three aftershock belts in the NE,NWW,and NW directions of has been obtained.The analysis reveals three rupture planes of strong events of MS7.8,MS7.1 and MS6.9 in the sequence.It indicates that the complex pattern is closely related to the earthquake source,and the NE-,NWW-and NW-trending regional fault zones,which have been revealed by the research of the pre-seismicity anomaly.In summary,the source is located in the junction of the three fault zones,and the rupture planes of the three strong events located in the source can be regarded as the locked segments on the three fault zones.On these grounds,the paper explains the complexity of the source and epicentral distribution of aftershocks.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 fundamental research funds of Institute of Earthquake Science,China Earthquake Administration (690206)
文摘By analyzing higher-accuracy location data of the Tangshan earthquake sequence,a clear distribution pattern of three aftershock belts in the NE,NWW,and NW directions of has been obtained.The analysis reveals three rupture planes of strong events of MS7.8,MS7.1 and MS6.9 in the sequence.It indicates that the complex pattern is closely related to the earthquake source,and the NE-,NWW-and NW-trending regional fault zones,which have been revealed by the research of the pre-seismicity anomaly.In summary,the source is located in the junction of the three fault zones,and the rupture planes of the three strong events located in the source can be regarded as the locked segments on the three fault zones.On these grounds,the paper explains the complexity of the source and epicentral distribution of aftershocks.
