科研之友
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摘要
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.
