利用远震接收函数探测襄樊台下方地壳厚度及泊松比

Crustal thickness and Poisson’s ratio beneath Xiangfan seismic station revealed by teleseismic receiver functions

利用襄樊台2015—2018年记录的震中距30°—90°,震级5.5级以上(含5.5级)的高信噪比远震波形事件,通过时间域反褶积方法提取台站接收函数,并用H-k扫描叠加方法得到台站下方地壳厚度和波速比。结果表明,襄樊台下方地壳厚度为35 km,略高于大陆地壳平均厚度33 km,处于西部山区厚地壳与中东部薄地壳的过渡地带。泊松比偏低,存在因区域内地壳应力积累发生微小地震的可能性。

In this study,we used high signal-to-noise ratio teleseismic wave form data with an epicenter 30°—90°and the magnitude above 5.5(including 5.5)of Xiangfan seismic station recorded during 2015—2018 to calculate the receiver functions using the time domain deconvolution method.The crustal thickness and vP/vS velocity ratio was obtained with the H-k stacking method.The results reveal that the crustal thickness beneath Xiangfan seismic station is 35 km,slightly higher than the average continental crustal thickness of 33 km.It is located in the transition zone between the thick crustal thickness of the western mountain area and the thin crustal thickness of the central and eastern parts.Poisson’s ratio is low and there is the possibility of minor earthquake due to the accumulation of regional crustal stress.