基于接收函数的郯庐断裂带南段及其周缘壳内结构研究  

Crustal Structure of the Southern Section and Surroundings of the Tan-Lu Fault Zone Based on Receiver Functions

作　　者：李婷婷 张岑[1] 范文华[1] 孙小航 朱峰[1] 孙业君[1] LI Tingting;ZHANG Cen;FAN Wenhua;SUN Xiaohang;ZHU Feng;SUN Yejun(Earthquake Administration of Jiangsu Province,Nanjing 210014,China)

机构地区：[1]江苏省地震局,江苏南京210014

出　　处：《防灾减灾工程学报》2024年第6期1465-1473,共9页Journal of Disaster Prevention and Mitigation Engineering

基　　金：三结合提升性课题(3JH-201902017);三结合一般性课题(3JH-202401028);江苏省地震局测震创新团队(202201)资助。

摘　　要：提取郯庐断裂带南段苏皖地区东西两侧40个宽频带固定台站记录的2015~2022年远震波形数据,采用远震P波接收函数方法,计算且筛选出1 758条高质量的接收函数,并结合H-K叠加搜索方法反演得到各台站下方的地壳厚度和泊松比值。结果表明:(1)研究区莫霍面起伏较大,地壳厚度介于28~36 km之间,平均地壳厚度约为32.6km;地壳厚度有明显块体分布特征,位于山地隆起的大别造山带和苏鲁造山带莫霍面埋深明显高于盆地或平原地区,同一块体内部因地形地貌和壳内物质的复杂性,也存在明显差异;地壳厚度以郯庐断裂带为界,大致呈现自西向东减薄特征;地壳厚度与研究区的地形地貌总体呈现对称关系,秦岭-大别造山带为研究区地壳厚度值最高区域。(2)研究区台站下方泊松比值主要介于0.20~0.29之间,跨度较大,表明壳内物质组成复杂;研究区平均泊松比值约为0.24,与全国大陆均值接近;位于山地隆起区域的部分台站泊松比值较高,分析认为可能与壳内涌入熔融物质或与铁镁物质的侵入有关;研究区泊松比与地壳厚度具有反相关系,地壳厚度高值处往往对应泊松比的低值区域。Extracting the teleseismic waveform data recorded from 2015 to 2022 by 40 broadband seis-mic stations on the east and west sides of the Tan-Lu fault zone in the Jiangsu-Anhui regions,1758 high-quality receiver functions were calculated and filtered using the teleseismic P-wave receiver func-tion method.The H-K superposition search method was then applied to obtain the crustal thickness and Poisson's ratio beneath each station.The results showed that:(1)The Moho interface in the study area showed significant undulations,with crustal thickness ranging from 28 to 36 km and an average crustal thickness of approximately 32.6 km.The crustal thickness was characterized with distinct block distribution,with the Moho interface burial depth in the Dabie and Sulu orogenic belts located in mountainous uplifts significantly greater than in basins or plains.Within the same block,notable varia-tions also occurred due to the complexity of topography and crustal composition.The crustal thickness showed a general thinning trend from west to east,demarcated by the Tan-Lu fault zone.There was a symmetrical relationship between the crustal thickness and the topography in the study area,with the Qinling-Dabie orogenic belt being the region of maximum crustal thickness.(2)The Poisson's ratio in the study area mainly ranged from 0.20 to 0.29,with a large span,indicating complex crustal composi-tion.The average Poisson's ratio in the study area was about 0.24,close to China's continental aver-age.Some stations located in mountainous uplift areas had higher Poisson's ratios,possibly due to the influx of molten material or the intrusion of iron and magnesium materials.Poisson's ratio in the study area showed an inverse correlation with crustal thickness,with higher crustal thickness often corre-sponding to regions with lower Poisson's ratio.

关 键 词：苏皖地区 郯庐断裂带 接收函数 地壳厚度 泊松比 

分 类 号：P315.3[天文地球—地震学]