【摘要】 华南沿海地区地壳厚度和泊松比分布是了解该地区板块运动和地球内部物质结构的重要依据.本文利用广东台网和福建台网共75个固定地震台记录到的2001—2008年远震波形的接收函数,通过H-κ叠加法获得了74个台站下方平均地壳厚度和泊松比值的有效估计,结合该区断裂分布、地震活动和地形地貌特征,得出以下结论:(1)该区地壳厚度范围在26~32km之间,由陆向洋、自北向南减薄.泊松比0.23~0.28,由陆向洋增加,地壳厚度与泊松比变化分别和地表地形呈正相关和负相关;(2)地壳厚度和泊松比呈块状和带状分布,对应该区的断裂活动,其过渡带变化地区与地震分布一致,震群区和地幔上隆区对应泊松比的急剧增加;(3)该区主要以中、酸性地壳物质为主,地壳厚度与泊松比在近海区的构造伸展作用和褶皱区的逆冲推覆作用影响下,分别呈正、负消长关系,揭示该区不同时代和不同区域构造演化模式的差异.更多还原

【Abstract】 The crustal thickness(H)and Poisson′s ratio(υ)are important for understanding the plate motion and the interior earth structure. We collected teleseismic receiver functions of earthquakes,which occurred from 2001 to 2008,from 75 permanent seismic stations of Guangdong and Fujian networks.In total 74 estimations of Handυwere obtained by making use of the H-κ method.Combining with characteristics of the fault distribution,seismicity and topography,several conclusions were achieved below.(1)Crustal thickness ranges from 26to32 km,reducing from land to sea and from north to south.Poisson′s ratio is 0.23~0.28,increasing from land to sea.Variations of H andυhave positive and negative correlations with surface topography,respectively.(2)Fault activity correspond to the block-like and band-shaped distributions of H andυ.Transitional variation zones of H andυspread in accordance withseismicity.Earthquake clusters and mantle upwelling are generally corresponding to the rapid increasing ofυ.(3)Crustal rocks in this area manly consist of intermediate and acidic minerals.Crustal thicknesses are positively and negatively related to Poisson′s ratio under actions of extensional tectonics offshores and thrusting structure in folded regions,respectively,revealing the diversified evolution models in different eras and districts.更多还原