Simulation of acoustic waves in 2D circular regions using the multi-block structured grid finite-difference method. - Fang, Changjiang; Zhang, Zhenguo; Ren, Hengxin; Zhang, Heng; Wang, Wenqiang; Lu, Zhaoyang; Zhan, Qiwei; Zhang, Wei; Huang, Qinghua; Chen, Xiaofei (Earthquake Science, 2025)