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EARTHQUAKE ›› 2020, Vol. 40 ›› Issue (1): 11-33.doi: 10.12196/j.issn.1000-3274.2020.01.002

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Research on Activity Characteristics of Strong Earthquakes in North China

YIN Xiao-fei, ZHANG Guo-min, SHAO Zhi-gang, WANG Peng, SUN Xin-zhe   

  1. Institute of Earthquake Forecasting, China Earthquake Administration, Beijing 100036, China
  • Received:2019-09-21 Online:2020-01-31 Published:2020-01-20

Abstract: North China is the most central area for politics, economy and culture of our country, and also one of the earthquake-prone areas in China. The historical record for seismic data in North China is earlier and more continuous, and it is an ideal site for strong earthquake activity studying. This paper has selected the M≥6.0 earthquake catalogue in the third and fourth active periods as the basic data to study the activity characteristics of strong earthquakes in North China. Firstly, the relations of strong earthquake activity levels to active-tectonic blocks and boundaries in North China are discussed. Then, the recurrent phase and episodic characteristics of strong earthquake activities from time and space in North China are analyzed. Finally, the cumulative and conditional probabilities of the M≥6.0 earthquakes in North China are calculated to evaluate earthquake occurrence in this region after five years. The results suggest ① the M≥6.0 earthquakes are mainly concentrated in active-tectonic boundaries, the M≥7.0 earthquakes all happened in active-tectonic boundaries, and the linear relation between seismic strain-releasing rates and tectonic deformation velocities of active-tectonic boundaries in North China; ② Because energy releases of activity curtains in the fourth seismic active periods are lower than that of the third seismic active periods, it seems that M≥6.0 earthquakes will occur in North China in the future; ③ There are obviously different major regions of strong earthquakes between the third and fourth seismic active periods in North China, earthquake activities of the fourth seismic period migrate eastward compared with the third seismic period; ④ If the current quiet episode of the M≥6.0 earthquakes ends in the beginning of 2020, the accumulated seismic probability of the M≥6.0 earthquakes is about 80%; and if the current quiet episode of the M≥6.0 earthquakes ends by the end of 2022, the conditional seismic probability is 50%. This study can provide significant reference for the analysis of overall seismic trend and medium-to-long term earthquake hazard prediction in North China.

Key words: Strong earthquake activities in North China, Active-tectonic blocks and boundaries, Recurrent phase characteristics of strong earthquake activities, Episodic characteristics of strong earthquake activities, Seismic hazard

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