摘要
天山造山带构造环境复杂,活动断裂带和强震分布广泛,且主要分布于阿尔泰山、天山、西昆仑—帕米尔弧形构造带上,尤以天山地区最为集中.迄今为止,天山造山带地区的主要断裂带的活动特征与孕震应力场特征之间的动力学机理尚未有清晰的认识.本文以GPS等实际观测数据为约束,建立有限元数值模型,计算了研究区域地壳形变、应力/应变积累速率、弹性应变能密度以及库仑应力变化率等关键因素.模拟计算结果显示地表速度场与研究区域实际GPS观测值基本一致,且主要断裂带上弹性应变能密度分布与实际地震活动性也基本吻合,验证了数值模型和结果的可靠性.结合最新的观测和数值模拟结果分析发现,研究区的断层和地震活动性主要受控于近南北向的主压应力,与主要观测特征相一致.同时,帕米尔高原北部边界带—塔什库尔干断裂(TKF)、天山造山带南边界的东侧—迈丹断裂(MDF)、兴地断裂(XDF)库仑应力增大明显,在未来强震发生的可能性较高,应予密切关注.
The tectonic environment of the Tianshan orogen is complex.Active fault zones,and large earthquakes are mainly distributed in the Altai mountains,Tianshan mountains and the west Kunlun-Pamir arc tectonic belt,especially in the Tianshan mountains.The dynamic mechanism between the active characteristics of the main fault zones in the Tianshan orogen and the seismogenic stress field has not been clearly understood.In this paper,a finite element numerical model is built with GPS and other actual observation data as constraints,and key factors such as crustal deformation,stress/strain accumulation rate,elastic strain energy density and Coulomb stress change rate are calculated.The simulation results show that the simulated surface velocity field is basically consistent with the actual GPS observations in the study area.And the distribution of elastic strain energy density in major fault zones is basically consistent with the actual seismicity,verifying the reliability of the numerical model and the results.Combined with the latest observation results and numerical simulation results,it is found that the fault and seismicity in the study area are mainly controlled by the principal compressive stress in the near north-south direction,which is consistent with the main observation characteristics.At the same time,the CFS of the northern boundary of the Pamir Plateau-Tashkurgan Fault(TKF),the eastern boundary of the Tianshan orogen-Maidan Fault(MDF)and Xingdi Fault(XDF)increase obviously,and they are highly likely to have large earthquakes in the future,which should be closely watched.
作者
王子韬
程惠红
董培育
庞亚瑾
张怀
石耀霖
WANG ZiTao;CHENG HuiHong;DONG PeiYu;PANG YaJin;ZHANG Huai;SHI YaoLin(Key Laboratory of Computational Geodynamics of Chinese Academy of Sciences,College of Earth and Planetary Sciences,University of Chinese Academy of Sciences,Beijing 100049,China;Key Laboratory of Earthquake Geodesy,Institute of Seismology,China Earthquake Administration,Wuhan 430071,China;The First Monitoring and Application Center,China Earthquake Administration,Tianjin 300180,China)
出处
《地球物理学报》
SCIE
EI
CAS
CSCD
北大核心
2020年第11期4037-4049,共13页
Chinese Journal of Geophysics
基金
国家杰出青年科学基金(41725017)
国家自然科学基金重大项目(41590864)
自然科学基金联合基金(U1839207)资助.
关键词
天山造山带
有限元数值计算
地壳形变
弹性应变能密度
Tianshan orogen
Finite element numerical calculation
Crustal deformation
Elastic strain energy density
