山东地区各向异性、地壳厚度及泊松比分布特征  

Characteristics of crustal anisotropy, thickness and Poisson’s ratio in Shandong region

作　　者：郑宏 范建柯[1,3] 李翠琳 苏道磊[4] ZHENG Hong;FAN JianKe;LI CuiLin;SU DaoLei(CAS Key Laboratory of Marine Geology and Environment,Institute of Oceanology,Chinese Academy of Sciences,Qingdao 266071,China;University of Chinese Academy of Sciences,Beijing 100049,China;Laboratory for Marine Geology,Qingdao National Laboratory for Marine Science and Technology,Qingdao 266061,China;Jinan Earthquake Monitoring Center,Jinan 250001,China)

机构地区：[1]中国科学院海洋研究所,中国科学院海洋地质与环境重点实验室,青岛266071 [2]中国科学院大学,北京100049 [3]青岛海洋科学与技术试点国家实验室,海洋地质过程与环境功能实验室,青岛266061 [4]济南市地震监测中心,济南250001

出　　处：《地球物理学进展》2021年第5期1905-1915,共11页Progress in Geophysics

基　　金：国家自然科学基金(41876043,41976052)资助。

摘　　要：山东地区位于华北东部,包含沂沭断裂带、鲁西隆起等重要构造单元,地质构造演化非常复杂,但目前尚缺乏对山东地区整体的地壳结构、壳内形变、壳幔耦合等方面的研究.本文基于该地区52个地震台站两年的波形记录,采用接收函数Ps转换波分裂和H-κ叠加的方法得到了研究区地壳各向异性、平均地壳厚度以及泊松比特征,为该地区的构造演化提供了重要的地震学约束.结果表明,研究区地壳结构存在较强的横向不均匀性.鲁西隆起南部地壳各向异性方向可能与断裂和地壳内部的构造拆离有关.泰山地区地壳厚度与泊松比呈现负相关,地壳各向异性不明显,表明泰山处在快速隆升阶段.胶东地区东部较小的地壳厚度和泊松比与地幔上涌和苏鲁造山带发育的超高压变质岩有关.沂沭断裂带南北段的地壳结构具有显著差异,南段地壳厚度与泊松比存在明显的横向变化,表明南段可能存在剧烈的地幔上涌.较厚的沉积层使得济阳凹陷内台站下方的泊松比偏小,而较薄的铁镁质下地壳层则可能是胶北隆起部分台站下方泊松比偏小的主要原因.Shandong region, located in the east of North China, is constituted by the Yishu fault zone, the Luxi Uplift and other tectonic units. With a complex tectonic evolution, this region has not been well understood due to scarcity of holistic study on the crustal structure and deformation and crust-mantle coupling. On the basis of two-year teleseismic waveforms recorded by 52 seismic stations in Shandong region, the crustal anisotropy, thickness and Poisson’s ratio are obtained by using methods of the converted wave splitting and H-κ stacking methods of receiver functions, which provide significant seismological constraints on the tectonic evolution of this region. The results show that the crustal structures in the study region are significantly heterogeneous. The fast-velocity directions of the crustal anisotropy in the southern part of the Luxi Uplift may be related with faults and detachment structures. The negative correlation between the crustal thickness and the Poisson’s ratio, as well as the weak anisotropy beneath the Mount Tai region indicate that the Mount Tai is experiencing rapid uplifting. The smaller crustal thickness and Poisson’s ratio in the eastern part of Jiaodong region are possibly related to mantle upwelling and the ultrahigh-pressure metamorphic rocks in the Sulu orogenic belt. The crustal thickness and Poisson’s ratio in the southern part of the Yishu fault zone exhibit strongly lateral variation, possibly indicating intensive mantle upwelling, which are different from those in the northern part of the Yishu fault zone. The thick sediment layers beneath some stations in the Jiyang Depression may result in small Poisson’s ratios, whereas the thinner mafic and femic lower crust may be responsible for the small Poisson’s ratios beneath some stations in the Jiaobei Uplift.

关 键 词：接收函数 地壳各向异性 地壳厚度 泊松比 山东地区 

分 类 号：P315[天文地球—地震学]