Monitor Temporal Variations Of The Travel Time And Amplitude In The Surface Data Collected From Hutubi,Xinjiang Airgun Experiment

Extracting accurate waveform information from the airgun data is key to mapping the detailed velocity structures and monitoring their temporal variations.In this the-sis,we eastablish a procedure for processing airgun data,eollected in Hutubi area,to obtain more stable stacked waveform records,which are modeled with the ID velocity structure in Hutubi area.Then,we introduce the recently developed wavelet propagator method to measure the travel time changes.This new method not only provides the travel time changes at different frequencies simultaneously but also performs error estimations.Furthermore,we demonstrate that surface wave amplitude could be an effective param-eter to monitor the temporal variations of the subsurface velocity structure.Surface wave amplitude ratio can overcome possible errors in travel time change measurements introduced by sudden changes of the airgun source energy.We also observed a good correlation between surface wave amplitude ratios and travel time changes,which can be explained by the focusing/defocusing effects accompanied by the velocity structure changing.