腾冲火山区的地壳厚度和平均泊松比研究

腾冲是青藏高原东南缘重要的第四纪火山活动区域,全新世以来的火山主要集中在腾冲盆地的中央,由北向南形成一个串珠状的火山链.为了深入探索这一火山区的深部结构和岩浆活动特征,我们在腾冲北部开展了为期一年的流动地震观测,利用接收函数方法计算了台站下方的地壳厚度、平均波速比和泊松比,研究结果揭示出测线下方地壳结构与岩浆活动及火山分布的对应关系.测线北部7个台站的地壳厚度在35.4~37.6 km之间,平均波速比为1.82~1.92、泊松比为0.28~0.31,其中马站附近莫霍面抬升幅度最大,与相邻地区莫霍面深度相差1~2 km,平均波速比和泊松比也达到最大值.相比之下,测线南端两个台站的地壳厚度接近40 km,平均波速比和泊松比仅为1.61~1.64和0.18~0.20,与测线北部7个台站的地壳结构相差甚大.分析表明地幔上涌对火山区莫霍面的局部抬升产生了一定影响,火山湖、黑空山、大-小空山和打鹰山下方应该存在一个相互联通的壳内岩浆囊.该岩浆囊在南北方向上的尺度约为20 km,热流活动以及幔源物质的侵入是地壳平均波速比和泊松比偏高的主要原因,它与热海附近的地温异常区分属两个不同的壳内岩浆存储系统.     

用接收函数研究川滇地区国家地震台下地壳厚度及波速比

本文利用远震接收函数的方法,对川滇地区的昆明、腾冲、成都和攀枝花等4个国家地震台的台基下方不同方向的莫霍面深度及波速比进行了研究和分析。结果表明:昆明地震台台基下方的莫霍面深度基本在50km左右,波速比为1.62～1.69,地壳厚度和波速比不因方向不同而发生明显的变化;腾冲地震台台基下方的地壳厚度有着比较明显的方向性,东北方向厚为40.7km,东南方向为49.7km,两个方向的波速比相差也很大,差值达到0.2;成都地震台台基下方莫霍面的深度在40km左右,但是东北和西南方向要加深8km,两个方向波速比相差0.13;攀枝花地震台台基下方的地壳厚度比较稳定,厚度在60km左右,波速比变化也不明显。     

唐海—商都地震台阵剖面下方岩石圈结构

2006年10月到2009年9月,中国地震局地球物理研究所在华北地区布设了250个流动地震台站,本文选取其中一条从唐海经过唐山、三河、北京、张家口到商都的宽频带地震台阵剖面作为研究对象.利用该剖面49个宽频带台站记录的191个远震数据进行了S波接收函数的计算,通过共转换点叠加成像对剖面下方的岩石圈结构进行研究,获得了剖面下方的岩石圈精细结构.Moho界面和岩石圈-软流圈界面清晰可见,剖面下方地壳厚度从西到东逐渐减薄,从42 km逐渐减薄至30 km左右,西部陆块岩石圈厚度从100 km逐渐减薄至70 km,中部和东部陆块岩石圈厚度变化相对平稳,介于60~80 km,表明剖面下方岩石圈遭受了大规模的明显减薄.结合其他地球物理方法研究结果,我们认为剖面下方华北克拉通东部陆块岩石圈减薄主要是由于热侵蚀作用引起的.     

中国华南地区地壳厚度与波速比分布特征及其地质意义

本研究利用中国国家地震台网336个固定地震台站记录的远震波形资料,通过P波接收函数H-κ分析估算了中国华南地区的地壳厚度和地壳平均波速比.研究结果显示,地壳厚度约为25~46 km,整体表现西深东浅的变化特点.研究区地壳厚度变化分别与布格重力异常和地形呈现负相关和正相关.扬子块体东部显示较低地壳波速比(<1.7)可能与地表沉积岩的存在相关.四川盆地内部的平均地壳波速比(约1.71~1.8)与全球大陆地盾/克拉通地区相当.但其周围地区地壳平均波速比明显增高(1.81~1.95),推测可能是克拉通形成过程中岩浆的底侵引起下地壳组分以铁镁质麻粒岩为主.华夏块体西部表现为薄的地壳厚度和低的地壳平均波速比(1.65~1.75),暗示该区基性下地壳物质的缺失可能与增厚的地壳发生拆沉有关.华夏块体东南段呈现出较高的地壳平均波速比(约1.77~1.86),地壳组成以中基性铁镁质为主,推断可能与晚中生代铁镁质岩浆底侵作用密切相关.     

利用接收函数方法研究腾冲地区S波速度结构

腾冲地区邻近印度板块与欧亚板块碰撞、俯冲的边界,地质环境和构造背景十分复杂,是我国地震、火山活动比较活跃的地区之一.本文采用最大熵谱反褶积方法提取腾冲地区1.0°×0.8°范围内5个流动数字地震台站的宽频带远震接收函数,反演得到台站下方0～100km深度范围的S波速度结构,分析讨论了该地区的深部构造特征.结果表明:1)腾冲地区地质结构存在明显的横向非均匀性;2)盈江断裂两侧莫霍面深度有较大差异;3)腾冲和高黎贡山之间是地壳厚度和S波速度变化的高梯度带;4)盈江断裂东南、新生破裂带以西附近地区存在明显的低速层;5)盈江断裂和新生破裂带都可能对火山区的熔融体具有阻隔作用.     

兴蒙造山带阿尔山火山群地壳厚度与波速比研究

利用架设在我国东北地区阿尔山火山区的宽频带流动地震台站记录的远震波形数据,采用P波接收函数H-κ叠加扫描方法,得到了阿尔山火山区的地壳厚度和平均波速比。结果显示:阿尔山地区的地壳厚度范围为33.9—37.9 km,整体呈西北厚东南薄的特点,火山带附近地壳较薄;地壳平均波速比范围为1.73—1.83,主要有柴河镇—明水河镇、伊敏德仁北部和天池镇三处高波速比区。结合前人研究结果推断, 阿尔山火山区薄的地壳和高波速比值可能是由地幔物质上涌、玄武岩浆底侵下地壳所致。      

中国东北-华北地区地壳厚度与泊松比及其地质意义

本文通过收集和综合分析已有的接收函数H-k研究结果,给出了中国东北-华北地区的地壳厚度与波速比/泊松比分布图.本研究表明该区地壳最薄的地方出现在松辽盆地和华北平原地区（28~35 km）;大兴安岭、燕山-太行地区的地壳厚度介于36~45 km范围,其中燕山造山带地壳厚度由东向西逐渐增加;而最厚的地方则出现在鄂尔多斯盆地西南缘（~55 km）.研究区平均波速比为1.76±0.05,较全球大陆平均值明显偏高,这可能与中、新生代以来该区显著的岩石圈减薄与破坏过程相关.其中地壳波速比最高的地方出现在山西地堑、长白山、大同-张家口等新生代火山区,意味着这些地区可能具有较高的地壳温度或存在广泛的壳内部分熔融.本文研究显示,大兴安岭造山带地区地壳厚度与波速比/泊松比成负消长关系,推测大兴安岭在形成过程中,地壳的增厚以长英质上地壳增厚为主.与大兴安岭地区不同,松辽盆地及周边地区地壳厚度与泊松比没有明显的相关性,表明松辽盆地可能具有复杂的形成与演化过程.     

东北地区至华北北缘地壳结构的区域差异: 地壳厚度与波速比的联合约束

本文通过对分布相对均匀的127个固定台站下方接收函数的H-κ叠加分析,并结合前人对97个线性密集流动台站的研究结果,获得了东北地区和华北克拉通北缘地壳厚度(H)与平均波速比(κ).结果表明研究区域地壳总体较薄,波速比变化复杂,地壳密度横向变化大,暗示着地壳在中—新生代经历了显著的不均匀破坏与改造.东北和华北北缘都存在明显的东西向差异.东北地区西侧兴蒙造山带地壳大致随着海拔增高逐渐增厚,H和κ分别主要在31~39 km和1.71~1.83之间变化,平均值分别为~35 km和~1.77;东侧吉黑褶皱带地壳厚度与海拔不成镜像关系,H和κ集中在28~37 km和1.72~1.89范围, 平均值分别为~33 km和~1.79.华北北缘西侧燕山带地壳由东往西逐渐增厚,H和κ主要在28~40 km和1.70~1.91范围内变化, 平均值分别为~34 km和~1.79.东侧辽东台隆地壳表现为中间厚四周薄,H和κ集中在29~35 km和1.71~1.83范围, 平均值分别为~32 km和~1.77.东北地区吉黑褶皱带相对薄的H和变化范围大的κ表明,该区域可能由于其自身的地壳结构复杂性和紧邻太平洋板块前缘从而在中新生代遭受到了与太平洋板块俯冲相关的更为强烈的地壳减薄与改造.华北北缘燕山带H和κ复杂的变化特征表明,该地区可能受到中亚造山带增生和太平洋板块俯冲的共同影响,从而发生了更为复杂的地壳改造变形.     

晋冀蒙交界地区的地壳厚度与泊松比特征

根据晋冀蒙交界地区固定台和流动台共计78个台站记录的高质量远震资料, 得到了共计6978个接收函数, 反演了晋冀蒙交界地区的地壳厚度与波速比结果。 结果显示, 研究区的地壳厚度在31~45 km, 变化幅度较大, 具有由东向西逐渐加厚的横向变化, 并且沿着东南—西北方向有渐变特征。 台站下方地壳速度比在1.63~1.90, 对应的泊松比在0.18~0.31, 具有明显的分块特征。 波速比相对较高的地区多为沉积盆地断陷中心地带及附近区域, 波速比较低的区域分布在太行山脉中段与吕梁山地区等隆起区域附近。 大同火山区波速比高于周边地区, 是火山剧烈活动引起地幔物质上涌的反映。 太行山山前断裂带附近的台站下方地壳平均速度比呈现由北向南逐渐减小的特征, 表明此区域地壳分层结构明显, 同时也反映了平原地区与山脉地区的地壳介质成分的差异。     

巽他大陆及其邻区的地壳结构及其构造意义:来自远震接收函数的约束

巽他大陆位于欧亚板块、印度—澳大利亚板块和太平洋板块俯冲汇聚区域,其地壳结构特征是揭示洋陆过渡带演化及物质能量交换机制的重要依据.本文对巽他大陆及其周缘 19 个宽频带地震台站记录的远震波形进行 P波接收函数分析和H-κ叠加处理,获取了每个台站下方的地壳厚度和平均地壳波速比信息.为了减少参数的主观选择对结果带来的不确定性,研究采用了多种参数组合、综合约束策略.将本文结果与前人 146 个宽频带台站接收函数的研究结果进行整合,我们获得了巽他大陆地区地壳厚度和平均地壳波速比分布,并统计分析了两者的相关性.结果显示:巽他大陆地壳总体较薄,平均地壳厚度约为32 km,远低于全球造山带平均值,而与全球拉张型地壳平均厚度较为接近,可能反映研究区地壳整体处于拉张应力状态;而呵叻高原盆地地区地壳相对较厚,平均约38 km,与周缘地区明显不同.火山弧地区平均地壳波速比普遍大于 1.81,甚至达 1.87以上,并且壳内广泛分布低速层,可能受到了火山弧地区熔融物质的影响;非火山弧地区平均地壳波速比则普遍小于 1.76,反映地壳组分以长英质成分为主;局部地区高于 1.81,甚至高达 1.99,表明地壳以铁镁质成分为主或存在部分熔融,可能与铁镁质岩浆底侵作用或地幔热物质上涌有关.中南半岛中西部、婆罗洲西北部和马来半岛中部莫霍面 Ps转换波和多次波不明显而且具有多峰特征,可能表明该区域经历了复杂的壳幔相互作用.巽他大陆地区地壳厚度和平均地壳波速比总体无明显相关性,说明上地壳和下地壳结构和成分横向变化复杂;但中南半岛内部呵叻高原附近和东南部火山区两者均呈负相关性,与周围地区明显不同.综合区域构造背景和其他多种地球物理观测,推测稳定的呵叻高原盆地阻挡了印支地块的侧向挤出,处于挤压应力环境并发生上地壳增厚;而东南部火山区则处于拉张应力环境并存在基性岩浆底侵,可能与地幔物质上涌有关.     

兴蒙造山带诺敏河火山群地壳厚度与波速比研究

利用布设于兴蒙造山带诺敏河火山群地区的宽频带流动地震台站资料,基于接收函数方法,获取了该地区的地壳厚度与波速比值.研究结果显示,该地区的地壳厚度介于32~38 km,莫霍面深度在空间上分布特征与五大连池为中心的火山带分布具有较好的一致性：沿着火山带延展方向地壳较薄.该地区的波速比介于1.74~1.84,波速比在空间上与地壳厚度变化具有一致性：高波速比主要集中于靠近五大连池火山带地区,向诺敏河火山和小古里河火山延展.研究认为：诺敏河火山与五大连池火山带可能具有相同的岩浆来源,可能与富钾岩石圈地幔拆沉作用造成的地幔热物质上涌有关.研究区地壳厚度与波速比呈现负相关关系,暗示该地区可能发生过岩浆底侵作用.     

Receiver function analysis for seismic structure of the crust and uppermost mantle in the Liupanshan area, China

A portable broadband seismic array was deployed from the northeast Tibetan Plateau to the southwest Ordos block, China. The seismic structure of the crust and uppermost mantle of the Liupanshan area is obtained using receiver function analysis of teleseismic body waves. The crustal thickness and Poisson's ratios are estimated by stacking the weighted amplitudes of receiver functions. Our results reveal complex seismic phases in the Liupanshan area, implying intense deformation at the boundary between the Tibetan Plateau and the Ordos block. The average crustal thickness is 51.5 km in the northeast Tibetan Plateau, 53.5 km in the Liupan Mountain and 50 km in the southwest Ordos block, resulting in a concave Moho beneath the Liupan Mountain. The Poisson's ratio of the Liupanshan area varies between 0.27-0.29, higher than the value of 0.25-0.26 to the east and west of the Liupan Mountain, suggesting partial melting in the lower crust. The variance in Poisson's ratio across the Liupan Mountain indicates notable changes in the crustal composition and mechanical properties, which may be formed by the northeastward flow of the Tibetan lower crust during the India-Eurasia collision.     

Lithospheric structure of NW Iran from P and S receiver functions

We computed P and S receiver functions to investigate the lithospheric structure beneath the northwest Iran and compute the Vp/Vs ratio within the crust of this seismologically active area. Our results enabled us to map the lateral variations of the Moho as well as those of the lithosphere–asthenosphere boundary (LAB) beneath this region. We selected data from teleseismic events (M_b?>?5.5, epicentral distance between 30° and 95° for P receiver functions and M_b?>?5.7, epicentral distance between 60° and 85° for S receiver functions) recorded from 1995 to 2008 at 8 three-component short-period stations of Tabriz Telemetry Seismic Network. Our results obtained from P receiver functions indicate clear conversions at the Moho boundary. The Moho depth was firstly estimated from the delay time of the Moho converted phase relative to the direct P wave. Then we used the H-Vp/Vs stacking algorithm of Zhu and Kanamori to estimate the crustal thickness and Vp/Vs ratio underneath the stations with clear Moho multiples. We found an average Moho depth of 48 km, which varies between 38.5 and 53 km. The Moho boundary showed a significant deepening towards east and north. This may reveal a crustal thickening towards northeast possibly due to the collision between the Central Iran and South Caspian plates. The obtained average Vp/Vs ratio was estimated to be 1.76, which varies between 1.73 and 1.82. The crustal structure was also determined by modeling of P receiver functions. We obtained a three-layered model for the crust beneath this area. The thickness of the layers is estimated to be 6–11, 18–35, and 38–53 km, respectively. The average of the shear wave velocity was calculated to be 3.4 km/s in the crust and reaches 4.3 km/s below the Moho discontinuity. The crustal thickness values obtained from P receiver functions are in good agreement with those derived by S receiver functions. In addition, clear conversions with negative polarity were observed at ~8.7 s in S receiver functions, which could be related to the conversion at the LAB. This may show a relatively thin continental lithosphere of about 85 km implying that the lithosphere was influenced by various geodynamical reworking processes in the past.     

青藏高原东南缘Moho面速度密度跃变研究

青藏高原东南缘地下深部结构的研究对了解青藏高原的变形机制和动力学过程具有重要意义.本文利用四川、云南固定台站记录到的远震波形资料,首先采用接收函数H-k叠加方法获得青藏高原东南缘台站下方的地壳厚度和波速比.进而利用接收函数一次转换波和多次波幅度信息确定了青藏高原东南缘Moho面上的S波速度和密度跃变.研究结果表明:研究区由南到北地壳厚度逐渐增加,从永德、沧源、孟连地区的33 km左右增至巴塘地区的69.7 km左右,厚度变化了近乎37 km.四川盆地和松潘甘孜块体南部的姑咱地区具有高泊松比、速度密度跃变较小特征,表明这两个地区含有较多铁镁物质.腾冲地区、龙门山西侧的汶川地区、四川盆地西南缘的沐川地区以及则木河断裂的石门坎至东川地区同属于高泊松比、速度密度跃变较大,显示这些地区壳内存在部分熔融.     

Erratum to: Lithospheric structure of NW Iran from P and S receiver functions

We computed P and S receiver functions to investigate the lithospheric structure beneath the northwest Iran and compute the Vp/Vs ratio within the crust of this seismologically active area. Our results enabled us to map the lateral variations of the Moho as well as those of the lithosphere–asthenosphere boundary (LAB) beneath this region. We selected data from teleseismic events (M_b > 5.5, epicentral distance between 30° and 95° for P receiver functions and M_b > 5.7, epicentral distance between 60° and 85° for S receiver functions) recorded from 1995 to 2008 at 8 three-component short-period stations of Tabriz Telemetry Seismic Network. Our results obtained from P receiver functions indicate clear conversions at the Moho boundary. The Moho depth was firstly estimated from the delay time of the Moho converted phase relative to the direct P wave. Then we used the H-Vp/Vs stacking algorithm of Zhu and Kanamori to estimate the crustal thickness and Vp/Vs ratio underneath the stations with clear Moho multiples. We found an average Moho depth of 48 km, which varies between 38.5 and 53 km. The Moho boundary showed a significant deepening towards east and north. This may reveal a crustal thickening towards northeast possibly due to the collision between the Central Iran and South Caspian plates. The obtained average Vp/Vs ratio was estimated to be 1.76, which varies between 1.73 and 1.82. The crustal structure was also determined by modeling of P receiver functions. We obtained a three-layered model for the crust beneath this area. The thickness of the layers is estimated to be 6–11, 18–35, and 38–53 km, respectively. The average of the shear wave velocity was calculated to be 3.4 km/s in the crust and reaches 4.3 km/s below the Moho discontinuity. The crustal thickness values obtained from P receiver functions are in good agreement with those derived by S receiver functions. In addition, clear conversions with negative polarity were observed at ~8.7 s in S receiver functions, which could be related to the conversion at the LAB. This may show a relatively thin continental lithosphere of about 85 km implying that the lithosphere was influenced by various geodynamical reworking processes in the past.     

利用接收函数方法研究喜马拉雅东构造结地区地壳结构

本文使用位于喜马拉雅东构造结地区布置的24个宽频带地震台站记录的远震波形数据,利用P波接收函数的方法研究了台站下方的Moho面深度、泊松比和地壳速度结构.结果表明,东构造结内Moho面深度呈现出自南西向北东方向逐渐变深的趋势,地壳厚度在54~60 km范围内,其中东久一米林走滑断裂带附近Moho面最浅,东构造结周围拉萨地块的Moho面深度在60 km以上.东构造结西部东久一米林走滑断裂带附近地壳泊松比较高.嘉黎断裂带南北两侧的泊松比差别较大,说明该断裂带两侧地壳结构存在显著差异.东构造结周边拉萨地块地壳内普遍存在低速层,分布在20~40 km深度范围内,厚度约为5~15 km.     

利用接收函数研究青藏高原东南缘的地壳上地幔结构

本文使用位于青藏高原东南缘的25个地震台站的远震数据,采用P波和S波接收函数的方法研究了台站下方的Moho深度、泊松比以及地幔过渡带的厚度.计算结果表明：① 青藏高原东南缘的地壳厚度由松潘—甘孜地体和羌塘地体的约60 km,向邻区的印支地体以及扬子板块分别减薄为约38 km和约42 km; ② 羌塘地体的泊松比主要集中范围为0.25～0.28,地壳物质组分主要为中基性岩石,推测与下地壳镁铁质成分的增加有关.松潘—甘孜块体、印支块体和扬子板块的泊松比为0.25～0.26,主要为中酸性岩石组分.缺乏高的泊松比(≥0.30)分布表明青藏高原东南缘的地壳不存在广泛的部分熔融,但是不排除局部部分熔融的存在;③ 青藏高原东南缘的羌塘地体内存在一个比较明显的、异常变化范围为10～26 km的地幔过渡带增厚区域,其对应着地幔过渡带内100℃～260℃的温度降低,可以推断与此异常区域的地幔过渡带内存在俯冲的板块有关.     

利用H-K叠加方法和CCP叠加方法研究中国东北地区地壳结构与泊松比

利用中国东北布设的流动地震台阵（116个）以及国家和区域台网（121个）的宽频带台站记录的824个远震事件,采用P波接收函数CCP叠加和H-K叠加两种方法获得了研究区详尽的地壳厚度图像.研究结果显示,两种方法获得的地壳厚度分布特征具有很好的一致性,中国东北下方地壳厚度存在明显的东西横向差异.重力梯度带西侧和佳木斯地块的台站下方地壳较厚,介于36~41 km之间,而在兴蒙槽地褶带中重力梯度带往东从36 km减薄至34 km左右.松辽盆地北侧、东侧和南侧地壳厚度较薄,为29~34 km,反映了该区复杂的地壳变形过程.CCP剖面显示郯庐断裂深切地壳,敦化—密山断裂下方莫霍面出现错断.H-K叠加得到的地壳平均泊松比显示,东北地区绝大部分台站下方的泊松比值较大,0.24~0.29.长白山、松辽盆地东部、燕山台隆东部和大兴安岭北部,泊松比值达到0.27~0.30,可能有幔源物质上涌,下地壳铁镁组分含量增加.     

CRUSTAL ANISOTROPY AND ITS TECTONIC IMPLICATIONS IN THE CHONGQING REGION

The receiver function which carries the information of crustal materials is often used to study the shear-wave velocity of the crust as well as the crustal anisotropy. However, because of the low signal-to-noise ratio in Pms(P-to-S converted phase from the Moho), the crustal anisotropy obtained by shear-wave splitting technique for a single receiver function usually has large errors in general. Recent advance in the analysis method based on Pms arrival time varying with the back-azimuth change can effectively overcome the above defects. Thus in this paper, we utilize the azimuth variations of the Pms to study the crustal anisotropy in Chongqing region for the first time. According to the earthquake catalogue provided by USGS, seismic waveform of earthquakes with magnitude larger than 5.5 and epicenter distance range of 30°~90° between January 2015 and December 2016 are collected from 14 broadband seismic stations of Chongqing seismic network. We carry out the bootstrap resampling to test the reliability of the radial maximum energy method for the observation data. In addition, we also applied the receiver function H-Kappa analysis in this paper to study the crustal thickness and Poisson's ratio. Our results show the crustal thickness ranges from 40~50km, and there is a thin and thick crust in the southern and northern Chongqing, respectively. The crustal average Poisson's ratio ranges from 0.23~0.31, the Poisson's ratio reaches the maximum value in the central part of Chongqing, while the Poisson's ratio in the northern and southern parts of Chongqing is obviously low. We obtain the crustal anisotropy from 9 stations in total. The delay time of crustal anisotropy distributes between 0.08s and 0.48s, with the average value of 0.22s. Among them, the CHS, QIJ and WAZ stations in central Chongqing have relatively large crustal delay time(>0.3s), followed by ROC station in the western Chongqing(0.25s), while the delay time in CHK station in northern Chongqing and WAS station in southern Chongqing are 0.08s, showing relatively weak crustal anisotropy. The fast polarization directions(FPDs)also change obviously from south to north. In southern Chongqing, FPDs are dominant in NNE-SSW and NEE-SWW, while the FPDs in WAZ station change to NWW-SEE, and the FPDs appear to be NW-SE in CHK in the northern Chongqing. In general, the FPDs are sub-parallel to the strikes of faults in most areas of Chongqing areas. Combined with other results from GPS observations, tectonic stress field and XKS splitting measurements, the main conclusions can be suggested as following:The cracks preferred orientation in the upper crust is not the main source of crustal anisotropy in Chongqing area. The crust and lithospheric upper mantle in the eastern Sichuan fold belt(ESFB)and Sichuan-Guizhou fault fold belt(SGFFB)are decoupled, and the deformation characteristics in the north and south parts of ESFB and SGFFB is different. The complex tectonic deformation may exist beneath the mountain-basin boundary, causing the fast directions of crustal anisotropy different from that in other areas of ESFB and SGFFB. The faults with different strikes may weaken the strength of average crustal anisotropy in some areas. The crustal deformation in southern Dabashan nappe belt(DNB)may be mainly controlled by the fault structure.