【摘要】 根据35个数字地震台站记录的云南地区1 999～2007年6429个近震的波形资料,采用遗传算法对S波位移谱的高频衰减进行拟合,得到19009条衰减算子t~*数据.根据这些衰减算子t~*数据,反演得到云南地区地壳Q值分布.结果表明,云南地区的地壳Q值分布存在显著的横向不均匀性,即红河断裂北侧地壳Q值整体偏低,而红河断裂南侧地壳Q值整体较高.云南地区1900年以来6级以上强震基本上位于低Q值区域,这可能由于强烈构造活动导致地壳产生大量裂隙,且裂隙中充满流体,从而表现为低Q值;但呈北西向的龙陵澜沧—耿马孟连一带的强震却位于高Q值区,这可能与该地区正发育一条新的构造带有关.此外,云南地区的高大地热流点(>80 mW/m~2)基本上位于低Q值区域,热流值与衰减值成负对应关系.更多还原

【Abstract】 Based on the waveform data of 6429 local earthquakes recorded on 35 stations of Yunnan during the period from 1999 to 2007,a data set of 19009 attenuation factor t~* is obtained by fitting the high-frequency attenuation of S wave spectra with genetic algorithm.The spatial distribution of Q is determined by inverting the data of t~* with seismic tomography.The results show that there is a significant lateral heterogeneity in Q distribution in Yunnan,namely,the Q on the north side of Red River fault is low and is high on the other side.The M≥6.0 earthquakes are basically located in low-Q region since 1900,which may be due to strong tectonic activity leading to a large number of fluid-filled pores.However,the strong earthquakes in NW-trending Longlin-Lancang-Gengma region are located in high-Q region,which may be explained by the development of a new fault in the region.High heat flow sites (> 80 mW/m~2) in this region are located in low-Q areas,indicating a negative correlation.更多还原