沿海滩涂区浅层地震不同类型激发震源适用性分析

Applicability analysis on different types of sources for shallow seismic detection in coastal tidal flats

受复杂地表地质条件影响,沿海滩涂区地质调查程度较低,限制了相关地质调查方法技术的发展水平。浅层地震勘探技术在沿海滩涂地质调查中作用显著,但其勘探设备在沿海滩涂的适用性问题制约了地震探测数据采集工作,尤其体现在激发震源的适用性问题上。文中针对沿海滩涂复杂的地表地质条件,在满足探测要求的前提下,以提高地震记录分辨率和信噪比、提高施工效率为目的,选取了轻便灵活的夯击震源、锤击震源、落锤震源和电火花震源开展高精度地震探测激发震源适用性对比分析试验研究,通过对比分析不同震源激发的地震记录得出结论:电火花震源激发得到的单炮记录反射波频率高、频带宽、同相轴连续性好、探测深度深、信噪比高、受风噪干扰影响小,且可有效提高浅层地震数据采集施工效率。实际应用效果表明,电火花震源在沿海滩涂潮间带区浅层地震探测中的适用性较好。

Affected by the complex surface geological conditions,the degree of geological survey in coastal tidal-flat areas is quite low,which limits the development level of relevant geological survey methods.Shallow seismic exploration technology plays an important role in the geological survey of coastal shoals.However,seismic data acquisition in this area is restricted by the applicability of exploration equipment,especially the source.In order to meet the detection requirement in coastal tidal flats and consider the complex near surface conditions,the authors carried out an experimental study of applicability analysis of shallow seismic sources,which also took the resolution,SNR and work efficiency into consideration.Light and flexible sources were selected in this paper,orderly including the tamping source,hammering source,drop-hammer source and sparker source.A comparison between different sources shows that spark source gets the best performance in such aspects as reflection wave frequency,frequency band,continuity in seismic events,detecting depth,SNR and noise resistance,which can also improve the acquisition efficiency of shallow seismic detection.The application result shows that spark source has a good applicability in shallow seismic detection for coastal tidal flats.