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根据欧亚大陆及西太平洋地区102个数字化台站记录的近万次地震事件的长周期垂直向瑞雷波资料,利用时频分析方法测量并筛选后共得到11213条质量较高的基阶瑞雷波群速度频散资料.纯路径频散的反演中同时计算方位各向异性,反演获得了欧亚大陆及西太平洋边缘海地区(10°E—150°E,10°S—80°N)8—200s共28个周期的瑞雷波群速度及各向异性空间分布图象.瑞雷波高分辨率层析成像表明,30—60s周期,以青藏高原为中心呈极低速分布;100—120s周期,速度差异幅度较大,在东亚东部及西太平洋边缘海,自北向南显示出一条宽2500—4000km,长约8000km的巨型低速异常带.相对海洋来说,欧亚大陆各向异性强度较弱且快波方向较复杂.由于受到印度板块与欧亚板块的碰撞,中国大陆西部的各向异性强度明显大于东部.
According to long-period vertical Rayleigh wave data of nearly 10,000 earthquakes recorded by 102 digital stations in Eurasia and the Western Pacific region, 11213 high-quality base-rank Swiss The velocity-dispersion data of the L-wave group are obtained, and the azimuthal anisotropy is also calculated in the inversion of the pure-path dispersion. The Eurasian continent and the marginal seas of the western Pacific (10 ° E-150 ° E, 10 ° S-80 ° N) The Rayleigh wave velocity and anisotropy distribution over a period of 8-200 s in a total of 28 cycles showed that Rayleigh wave tomography showed extremely low velocity distribution around the Tibetan Plateau at 30-60 s intervals, In the east of East Asia and the margin of the western Pacific Ocean, a large low-velocity anomalous belt with a width of 2500-4000km and a length of 8000km is shown from the north to the south during the 100-120s period. The anisotropy is weaker and the fast-wave direction is more complicated, and due to the collision between the Indian plate and the Eurasian plate, the anisotropy in western China is obviously greater than that in the east.