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云南(21~29°N,97~106°E)地处印度板块与欧亚板块中国大陆碰撞带的东缘,是中国大陆最活跃的地震活动区域之一,其地震活动频度高、震级大、分布广,属于板缘、板内地震混合型地区.本研究采用中国地震科学台阵探测在南北地震带南段布置的367个流动地震台站记录到的波形数据,人工挑选出良好约束的,ML震级>3.0的近震P波走时数据,采用VELEST算法,联合反演得到了研究区的一维P波速度结构和震源参数.结果表明,云南地区一维P波速度模型在0和30 km之间速度介于5.96~6.60 km/s之间;在30到40 km之间的下地壳P波速度值为6.60~6.80 km/s;上地幔顶部平均P波速度为7.80 km/s,低于全球大陆速度模型均值(8.04~8.10 km/s).基于新模型的地震活动性分析表明云南地区地震事件大多发生在中上地壳(<20 km),约20 km处地震活动性最强且各个震级范围地震均有发生,可能指示该深度范围活跃的构造运动和复杂的应力状态.
Yunnan (21-29 ° N, 97-106 ° E) is located on the eastern margin of the collision zone between the Indian and Eurasian plates in mainland China. It is one of the most active seismic regions in mainland China with high frequency of seismic activity and magnitude Large and widely distributed, belongs to the plate edge, intraplate mixed area.In this study, the waveform data recorded by 367 mobile seismic stations deployed in the southern segment of the North-South Seismic Belt were detected by China Seismological Science Array and manually selected the good constraints , The P-wave velocity structure and source parameters of the one-dimensional P wave in the study area were obtained by using the VELEST algorithm and the ML inversion with the ML magnitude> 3.0.The results show that the one-dimensional P- The velocity of the lower crust P between 30 and 40 km is 6.60 ~ 6.80 km / s and the average P wave velocity at the top of the upper mantle is 7.80 km / s (8.04 ~ 8.10 km / s) .According to the new model, the analysis of seismicity shows that most of the earthquakes in Yunnan region occur in the middle and upper crust (<20 km), and the seismicity is about 20 km Strong earthquakes in all magnitude ranges occur and may indicate tectonic movements of this depth range And complex stress state.