为进一步加深对大容量气枪震源激发的地震波传播特性的认知，利用福建海陆多个气枪震源固定激发点重复激发的实验数据，通过线性叠加和仿真技术得到等效单次激发高信噪比速度和位移记录，然后利用不同震中距的位移峰值计算不同固定点气枪激发的等效震级，进而建立等效震级、震中距和速度峰值的衰减关系。结果表明：①震中距为0～270km时，大容量气枪单次激发得到的速度峰值为700～4nm/s，位移峰值为200～0.2nm；②总容量为8000 in³的气枪震源P波等效震级为0.181～0.760，S波等效震级为0.294～0.832，总容量为12000 in³的气枪震源P波等效震级为0.533～0.896，S波等效震级为0.611～0.946，气枪震源激发产生的S波能量大于P波能量，激发环境不同，激发效能相差较大；③速度峰值随等效震级增大而增大，随震中距增大而减小，P波速度峰值三分量中垂直分量最大，S波相反，其垂直分量最小，二者水平分量相近。研究结果可为定量判断气枪震源激发的地震波的传播能力以及利用气枪震源进行深部探测或监测的观测系统的设计提供重要依据。

In order to further deepen the understanding of seismic wave propagation characteristics induced by the large-volume airgun source,experimental data from multiple fixed excitation points in Fujian Province were used to obtain the equivalent single excitation,high signal-to-noise ratio velocity and displacement records by linear stack and simulation techniques. Then the displacement peak of different epicenter distances was used to calculate the equivalent magnitude of the airgun source excitation at different fixed excitation points so as to establish the attenuation relationship between equivalent magnitude,epicenter distance and velocity peak. The results show that:① During the epicenter distance from 0km to 270km,the velocity peak range of the large-volume airgun single shot is about 700~4nm/s,and the displacement peak range is about 200~0.2nm/s. ② The equivalent magnitude of the P-wave from the airgun source with a total capacity of 8000 in³ is 0.181~0.760,and the equivalent magnitude of the S-wave is 0.294~0.832. The equivalent magnitude of the P wave from the airgun source with a total capacity of 12000 in³ is 0.533~0.896,and the equivalent magnitude of the S-wave is 0.611~0.946. The S-wave energy is greater than the P-wave energy,and the excitation efficiency varies greatly with different excitation environment. ③ The velocity peak increases with the increase of the equivalent magnitude,and decreases with the increase of the epicentral distance. The vertical component of the P-wave velocity peak is the largest among the three components,while the S-wave has the smallest vertical component and similar horizontal components. Hence,the research results can provide an important basis for the quantitative judgment of the seismic wave propagation distance of the airgun source and the design of the observation system in deep exploration or monitoring with airgun source.

P315

国家自然科学基金项目（41474071）资助