Abstract: Because the source signal of airgun is weak, it is easy to be disturbed by external noise or earthquake, so its true amplitude is covered.If these interference records are directly involved in the superposition, they will easily lead to unreliable amplitude information and affect the superposition effect.In order to eliminate the interference effects, this paper proposes the methods of probability screening and noise model screening amplitude superposition. Based on the experimental data of airgun in Longmentan Reservoir and Shaxikou Reservoir in Fujian Province in June 2018, the application effects of the two methods are tested in terms of the ability of eliminating interference, waveform shape and amplitude, and the advantages and disadvantages of the two methods are compared.The results show that: ① the two screening methods can effectively remove the abnormal interference, and the waveform shape and maximum amplitude of the airgun signal after processing are basically consistent with the direct linear superposition; ② the fixed network generally has detailed information of instrument parameters, and the noise spectrum method can easily confirm the operation status of the station and screen out the abnormal station in time; for the mobile station with unknown information such as sensitivity, noise model screening method is limited in use, while the probability screening method is concise and applicable.

Key words: Airgun source, Amplitude superposition, Eliminating interference