Study on Crustal and Lithosphere Thicknesses of Tengchong Volcanic Area in Yunnan

Abstract

AbstractTeleseismic waveform data recorded by 9 broadband seismic stations of Tengchong volcanic seismic monitoring network were used to study crustal thickness, Poisson's ratio and the depth of the lithosphere‐asthenosphere boundary (LAB) using the P and S receiver functions method. The results are as follows: ➀ The Moho depth ranges from 33.5 to 38.0km beneath Tengchong volcanic area; ➁ The Poisson's ratios in Tengchong volcanic area mainly range from 0.26 to 0.32, and the Poisson's ratios beneath 6 stations are greater than 0.29, which may be caused by the increased mafic rocks in crust where may exist 2 magma chambers; ➂ The LAB depth beneath Tengchong volcanic area ranges from 78.2 to 88.0 km. There is an obvious rise of the LAB and lateral variations are very large. The obvious dome of lithosphere in Tengchong volcanic area is caused by asthenosphere upwelling (upsurge of thermal mantle material) as well as lithosphere extension and thinning.