Sedimentary structures beneath the Northern Bohai basin constrained by the autocorrelation of receiver function
Significant amplification of seismic ground motion in sedimentary basins has been observed in the post-earthquake investigation of some moderate or large earthquakes.The large impedance contrast between soft sediments and underlying bedrock can prolong and amplify seismic ground motions,leading to the aggravation of earthquake damage.Reliable sedimentary structures and fundamental resonance frequency are useful for the ground motion estimation and seismic hazard analyses.In this study,P wave receiver function are calculated using teleseismic events recorded by 43 temporary stations in the Bohai Bay area.Receiver function autocorrelation are then used to determine the fundamental frequency of sedimentary layers,which is further used to estimate the sediment thickness in each site according to the empirical relationship.The fundamental frequencies decrease from northeast to southwest in the study area.The fundamental frequencies vary from 0.30 to 0.77 Hz and the sediment thicknesses vary from 120 to 500 m in the northeast of the study area.The fundamental frequencies of most stations in the southwest of study area are lower than 0.30 Hz,and the sediment thicknesses are between 500 and 1252 m.Our estimations of fundamental frequencies are in good agreement with those from HVSR techniques.Comprised to the results from existing seismic reflection and borehole data,we speculated that the large impedance contrast may be associated with interface between the unconsolidated sedimentary cover layer of the late Tertiary-Quaternary(N+Q)and consolidated sediment.
Autocorrelation of receiver functionSedimentary structureBohai Bay basin
NETL
NSTL
万方数据
