Abstract We successively adopt H-k stacking of receiver functions (RFs) and joint inversion of RF and surface wave dispersion with Gaussian factors of 1.0, 2.0 and 3.0 to invert the crustal thickness (H), average Vp/Vs ratio (k) and S-wave velocity beneath 146 broadband seismic stations in the middle-southern segments of the Tanlu Fault Zone (TLFZ) and adjacent regions. These observations, together with previous geologic and geophysical studies, are further used to investigate Phanerozoic tectonic evolution in the study region and the seismogenic environment of the Tancheng Ms 8.5 earthquake. Our results show that the Moho depth and k generally range from 25 to 38 km and 1.65–1.95, respectively. The study region is roughly divided into three parts with different crustal structures from north to south, based on the Cretaceous Tiefogou fault and Triassic Lu'an fault and their extensional profiles, which may reflect different responses to the westward subduction of the Paleo-Pacific and Pacific Plates in the Mesozoic-Cenozoic. In addition to the observed uplifted Moho, high k and vertically alternating high-/low-velocity layers, lateral variations in S-wave velocity and junctions of multiple faults are imaged beneath the Tancheng earthquake zone, which may also contribute to the occurrence of strong earthquakes.

中文翻译：

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受多频接收函数和面波数据约束的郯庐断裂带中南段及邻区地壳结构

摘要 我们先后采用接收函数(RFs)的Hk叠加和RF与面波色散的联合反演，高斯因子分别为1.0、2.0和3.0，反演地壳厚度(H)、平均Vp/Vs比(k)和S-郯庐断裂带（TLFZ）及邻近地区中南段146个宽带地震台站下的波速。这些观测与以往的地质和地球物理研究相结合，将进一步用于研究研究区显生宙构造演化和郯城8.5级地震的发震环境。我们的结果表明，莫霍面深度和 k 通常分别介于 25 至 38 公里和 1.65 至 1.95 之间。研究区从北向南大致分为地壳结构不同的三个部分，基于白垩系铁佛沟断裂和三叠系六安断裂及其伸展剖面，可能反映了中新生代古太平洋和太平洋板块向西俯冲的不同响应。除了观测到的抬升莫霍面、高 k 和垂直交替的高/低速层外，郯城地震带下方还对横波速度的横向变化和多条断层的交汇处进行了成像，这也可能有助于强震的发生。地震。