人工地震测深揭示云南中部地区不同构造单元地壳结构特征
邓晓果,王夫运,马策军,杨卓欣

(中国地震局地球物理勘探中心,河南 郑州 450003)

云南中部; 人工地震; 地壳速度结构; Moho面

The Crustal Structure Characteristics of Different Tectonic Units in Central Yunnan Revealed by Artificial Seismic Sounding
DENG Xiaoguo,WANG Fuyun,MA Cejun,YANG Zhuoxin

(Geophysical Exploration Center of China Earthquake Administration,Zhengzhou 450003,Henan,China)

central Yunnan Province; artificial seismic source; crustal velocity structure; the Moho discontinuity

DOI: 10.20015/j.cnki.ISSN1000-0666.2022.0056

备注

基于24°N线一带横穿云南中部地区的人工地震测线镇康—泸西剖面的11次人工地震爆破记录,利用震相追踪分析方法,拾取了沿剖面的壳内主要折射和反射震相,结合一维地壳分层模型对这些震相到时进行了走时拟合,获得了沿镇康—泸西剖面的地壳一维速度结构模型。结果表明:沿剖面地壳各界面形态由西向东呈现逐渐增厚的特征,中下地壳厚度变化与莫霍面基本一致,三江褶皱系以东的扬子地台和华南褶皱系上地壳逐渐减薄,扬子地台内部玉溪至弥勒一带上地壳增厚。
We analyse the data from the artificial seismic sources on a wide-angle,reflection/refraction profile,the Zhenkang-Luxi seismic sounding prolife along the 24°N latitude line in central Yunnan Province,and pick Pg and Pn phases of the refracted wave,P1,P2,Pm of the reflected wave.On the basis of the one-dimensional,velocity-structure model,we use the trial-and-error method to fit all the travel-time curves of the seismic phases,then we obtain the one-dimensional,velocity-structure model of the Crust along the Zhenkang-Luxi profile.The results show that the Crust obviously thickens along the profile from west to east,the intra-discontinuity of the mid-and lower-Crust is coincident with the variation of the Moho.The upper Crust of the South China fold system and the Yangtze Block located to the east of the Sanjiang fold system is becoming thin.The upper Crust from Yuxi to Mile in the Yangtze Block is thickening.