运用H-k扫描和人工读取震相到时两种方法对比研究云南地区地壳结构
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摘要
利用云南及其邻区59个宽频地震台站记录到的30°~100°远震资料,采用P波接收函数方法对云南地区的地壳厚度和地壳平均泊松比分布进行分析。研究结果显示:用H-k扫描和人工读取震相到时两种方法得到的云南地区地壳厚度和泊松比分布情况较为吻合。研究区域内Moho面埋深南浅北深,横向变化达30~40 km。在川滇菱形块体东南缘,地壳厚度等值线呈东南向舌状突出。泊松比呈块体分布特征,断裂两侧差异显著。高泊松比的分布主要集中在滇缅泰块体内和研究区域北部以及小江断裂附近,这与该区处于印度板块与欧亚板块碰撞俯冲前缘的特殊地理位置有关。
Using the selected earthquakes whose epicenter distance is from 30° to 100° recorded by 59 broad-band stations in Yunnan and its adjacent region,we study the crustal thickness and the distribution of poisson ratio in Yunnan by P wave receiver function technology. The main results are obtained as follows: the crustal thickness and the distribution of Poisson ratio in Yunnan are coincident by using H- k algorithm and direct picking the time delays of phases respectively. The lateral variation of the M oho depth is close to 30 ~ 40 km and it is shallowin the south and deep in the north in Yunnan region. The contour line of crustal thickness shows the prominent tongue protrusion in ES in southeast edge of Sichuan-Yunnan Lozenge Block,which reflect the influence of the east-toward flowmaterials in the Qinghai-Tibetan Plateau hindered by Sichuan Basin,and turn to escaping in ES on Yunnan area. The Poisson ratio is characterized with block distribution and has remarkable difference on both sides of the fault. The distribution of high poisson ratio is mainly concentrated in Yunnan-M yanmar-Thailand Block,the north of the study area and around the Xiao-jiang Fault,which relates to the study area located at leading edge of the collision and subduction of Indian plate with Eurasian plate.
Using the selected earthquakes whose epicenter distance is from 30° to 100° recorded by 59 broad-band stations in Yunnan and its adjacent region,we study the crustal thickness and the distribution of poisson ratio in Yunnan by P wave receiver function technology. The main results are obtained as follows: the crustal thickness and the distribution of Poisson ratio in Yunnan are coincident by using H- k algorithm and direct picking the time delays of phases respectively. The lateral variation of the M oho depth is close to 30 ~ 40 km and it is shallowin the south and deep in the north in Yunnan region. The contour line of crustal thickness shows the prominent tongue protrusion in ES in southeast edge of Sichuan-Yunnan Lozenge Block,which reflect the influence of the east-toward flowmaterials in the Qinghai-Tibetan Plateau hindered by Sichuan Basin,and turn to escaping in ES on Yunnan area. The Poisson ratio is characterized with block distribution and has remarkable difference on both sides of the fault. The distribution of high poisson ratio is mainly concentrated in Yunnan-M yanmar-Thailand Block,the north of the study area and around the Xiao-jiang Fault,which relates to the study area located at leading edge of the collision and subduction of Indian plate with Eurasian plate.
引文
陈佳.2010.利用基阶瑞利面波反演云南地区地壳及上地幔Qβ结构[D].昆明:云南大学.
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贺传松,王椿镛,吴建平.2004.用远震接收函数研究滇西地区的深部结构[J].地震学报,26(3):238-246.
胡家富,苏有锦,朱雄关,等.2003.云南的地壳S波速度与泊松比结构及其意义[J].中国科学,33(8):714-722.
黄金莉,赵大鹏,郑斯华.2001.川滇活动构造区[J].地球物理学报,44(增刊):127-135.
阚荣举,林中洋.1986.云南地壳上地慢构造的初步研究[J].中国地震,2(4):50-61.
李永华,吴庆举,田小波,等.2009.用接收函数方法研究云南及其邻区地壳上地幔结构[J].地球物理学报,52(1):67-80.
刘祖荫,皇甫岗,王椿镛,等.2000.“腾深99工程”的设计思路与方案[J].地震研究,23(2):143-147.
汪缉安,徐青,张文仁.1990.云南大地热流及地热地质问题[J].地震地质,12(4):367-377.
徐青.1992.云南大地热流及其大地构造意义[J].大地构造与成矿学,16(3):285-299.
赵永贵,钟大赍,刘建华,等.1992.地震层析地质解释原理及其在滇西深部构造研究中的应用[J].地质科学,(2):105-113.
Langston C.A..1979.Structure under Mount Rainier,Washington,inferred from Teleseismic Body Wave[J].J.Geophys Res.,84(4):4749-4762.
Zhu,L.P.,Kanamori.2000.Moho Depth Variation in southern Californiafrom Teleseismic Receiver Functions[J].J.Geophy.Res.,105(B2):2969-2980.
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