论文部分内容阅读
We analyzed teleseismic waveforms recorded by 36 stations near Bohai Sea region and obtained 2 248 high quality receiver functions.The crustal thickness (H) and average crustal vP/vS ratio (κ) as well as the Poisson’s ratios beneath 34 stations were estimated using the H-κ stacking method.The results indicate that crustal thicknesses near the Liaoning province range from 30.0 to 35.5 km,and the corresponding vP/vS ratios vary from 1.72 to 1.89 which corresponds to Poisson’s ratio with a range from 0.243 to 0.305.We also apply a common conversion point (CCP) stacking method of receiver function (RF) to image the upper mantle discontinuity structure beneath Bohai Sea region.Both the 410-km and the 660-km discontinuities (hereafter called the 410 and the 660) show clearly in the study region.The transition zone (TZ) thickness shows a different picture from the west to the east of the study region,which is a little bit thicker than that of the global average in the west of longitude 122°E,however,thinner in the east of longitude 122°E.We suggested that the dehydration of sinking slab into the lower mantle or a small-scale mantle plume from the lower mantle generated hot upwelling beneath this region.
We analyzed teleseismic waveforms recorded by 36 stations near Bohai Sea region and obtained 2 248 high quality receiver functions. The crustal thickness (H) and average crustal vP / vS ratio (κ) as well as the Poisson’s ratios beneath 34 stations were estimated using the H-κ stacking method. The results indicate that crustal thicknesses near the Liaoning province range from 30.0 to 35.5 km, and the corresponding vP / vS ratios vary from 1.72 to 1.89 which corresponds to Poisson’s ratio with a range from 0.243 to 0.305.We also apply a common conversion point (CCP) stacking method of receiver function (RF) to image the upper mantle discontinuity structure beneath Bohai Sea region. Both the 410-km and the 660-km discontinuities (hereafter called the 410 and the 660) show clearly in the study region. The transition zone (TZ) thickness shows a different picture from the west to the east of the study region, which is a little bit thicker than that of the global average in the west of longitude 122 E, however, thinner in the east of longitude 122 ° E.We suggested that the dehydration of sinking slab into the lower mantle or a small-scale mantle plume from the lower mantle generated hot upwelling beneath this region.