Investigation on coda wave attenuation in shallow media using dense array data from airgun and natural seismic sources

Accurate shallow media Q value parameters are essential for engineering applications such as ground motion simulation. This study focuses on the Binchuan Basin in Yunnan Province, China, and employs the Sato single-scattering model based on dense array data from both airgun source and natural earthquake sources to investigate the accurate coda wave Q value (Qc) distribution characteristics of shallow media in the region. The results indicate that the Qc values obtained in this study fall between those of the near-surface and deep media. By quantitatively analyzing the effects of station spacing of dense arrays and epicenter distance on the calculation results, we find that for engineering applications such as near-site ground motion simulations, the minimum station spacing can be controlled at approximately 8 km, whereas the spacing of stations can be controlled at less than 4 km to obtain the spatial distribution characteristics of the Qc values. It is preferable to control the epicenter distance within 40 km to obtain richer shallow media information without considering the effect of source depth. This study provides new insights into the application of dense array data from airgun and natural sources for engineering seismology and shallow structure detection.