Abstract：On the basis of the drilling data at a seismostation in Shanghai, the absorption medium model of cover and deep crust layer was established. The absorption and attenuation of airgun wavelet in the absorption medium were analyzed. The relation between the fault length which can be resolved and the depth of the earth layer. The results show that the signal’s energy decays faster within 5 km than within deep crust, and with the increases depth of the attenuation rate reduces. In depth of 25 km, the attenuation reaches 93 dB. When main frequency of the air gun’s wavelet is 6 Hz,the attenuation of wavelet is very small (the decay rate of lowfrequency can be ignored), the depth of the earth layer which can be resolved from 75 m increases to 290 m gradually.
