Crustal layering in Sichuan basin and surrounding regions:Constraint from improved sequential H-κ stacking of receiver functions
H-κ stacking with receiver functions has been widely adopted in extracting crustal structure beneath a single station.To constrain sediment and basement crustal structure beneath basins,a sequential H-κ stacking has been proposed.In application,for stations located above unconsolidated sediments and hard-rock sites which could be identified manually,the sequential H-κ stacking and single-layer H-κ stacking have been applied,respectively.This processing is relatively inefficient.To overcome the limitation,we extend the sequential H-κ stacking.Synthetic tests show that the improved sequential H-κ stacking can be used for both single-layer and two-layer crust models,and is applied for large datasets efficiently.Moreover,crustal layering has been investigated with the improved sequential H-κ stacking by using seismic data recorded from the regional permanent stations of the Sichuan basin and adjacent regions for 7 years,as well as from temporary stations deployed in the Weiyuan area.Our result shows that some stations in the central and northern Sichuan basin have a sediment thickness of 4.6～6.7 km,with average Vp/Vs ratios of about 1.9～2.9.The Conrad discontinuity is obvious beneath some stations in the southern Sichuan basin,with depths of 21～25 km.Thus it is estimated the upper crust thickness accounts for～56％of the entire crust.Crustal thickness varies across the two sides of the Longmenshan fault,and relatively high Vp/Vs ratios being located in the southern segment of this fault.Additionally,a doublet Moho structure appears beneath the Huayingshan fault locally.
万方数据
