Abstract：Dynamite source is one of the main excitation modes adopted in land seismic acquisition. Yet few relevant studies are conducted on explosion mechanism of dynamite source recently. Firstly in this paper,a quantitative study on the shock waves generated by explosive effect in rocks is achieved,and the relationship of cavity pressure varied with time during the process of cavity extension is obtained. Then the wave phenomenon in elastic media caused by cavity pressure is discussed,and the analytical solution of seismic wavelet displacement is derived. Finally the factors which influence the forming of seismic wavelets are analyzed based on model tests,and defects caused by commonly used unit impulse are modified. This is meaningful to nearsource wave field study and improvement of excitation effect.
