地震研究

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 Moho depth is close to 30～40 km and it is shallow in 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 flow materials 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-Myanmar-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.

引言
1 资料选取
2 原理与方法
3 数据处理
4 结果和讨论
5 结论

图1 云南地区地形及地震台站分布图<br/>Fig.1 Topography and distribution of seismic stations in Yunnan region

图1 云南地区地形及地震台站分布图
Fig.1 Topography and distribution of seismic stations in Yunnan region

图2 远震事件分布图<br/>Fig.2 Distribution of teleseismic events

图2 远震事件分布图
Fig.2 Distribution of teleseismic events

图3 富宁台站单条接收函数<br/>Fig.3 A single receiver function of Funing Station

图3 富宁台站单条接收函数
Fig.3 A single receiver function of Funing Station

图4 富宁台P波接收函数的叠加<br/>Fig.4 Stacking of receiver function of P wave of Funing Station

图4 富宁台P波接收函数的叠加
Fig.4 Stacking of receiver function of P wave of Funing Station

图5 H-k扫描求取富宁台站下方地壳厚度和波速比<br/>Fig.5 The crust thickness and poisson ratio beneath Funing Station by H-k scanning

图5 H-k扫描求取富宁台站下方地壳厚度和波速比
Fig.5 The crust thickness and poisson ratio beneath Funing Station by H-k scanning

图6 黑龙潭地震台H-k扫描结果<br/>Fig.6 The H-k scanning result of Heilongtan Station

图6 黑龙潭地震台H-k扫描结果
Fig.6 The H-k scanning result of Heilongtan Station

图7 地壳厚度一致性分析<br/>Fig.7 Consistency analysis of crust thickness

图7 地壳厚度一致性分析
Fig.7 Consistency analysis of crust thickness

图8 两种方法获得的云南地区地壳厚度等值线图(a)H-k扫描方法结果;(b)读取震相到时方法结果<br/>Fig.8 The contour map of crust thickness in Yunnan region by two methods (a)the result of H-k scanning;(b)the result of direct picking of the time delays of phases

图8 两种方法获得的云南地区地壳厚度等值线图(a)H-k扫描方法结果;(b)读取震相到时方法结果
Fig.8 The contour map of crust thickness in Yunnan region by two methods (a)the result of H-k scanning;(b)the result of direct picking of the time delays of phases

图9 云南地区地壳平均泊松比等值线图(a)H-k搜索扫描结果;(b)人工读取震相到时方法结果<br/>Fig.9 The contour map of average poisson ratio in the crust of Yunnan region(a)the result of H-k scanning;(b)the result of direct picking of the time delays of phases

图9 云南地区地壳平均泊松比等值线图(a)H-k搜索扫描结果;(b)人工读取震相到时方法结果
Fig.9 The contour map of average poisson ratio in the crust of Yunnan region(a)the result of H-k scanning;(b)the result of direct picking of the time delays of phases

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备注

引言

1 资料选取

2 原理与方法

3 数据处理

4 结果和讨论

5 结论

期刊信息