Sinkholes and cavities can represent serious hazards to human safety and urban infrastructures, cause roadbed subsidence, and so on. It is therefore essential to evaluate various sinkholes in different depths and sizes to assess the risk of collapse. This paper evaluates the effect of different cavities on Rayleigh-wave propagation and body (P) wave refraction. Rayleigh (R) wave propagation is analyzed according to the classical multi-channel analysis of surface waves (MASW) method also considering the R-wave backscattering. Synthetic seismic traces are computed by means of finite element modeling (FEM) for cavity and intrusion at different depths and sizes. Furthermore, field acquisition data is used to verify the detection effect of a cavity on R- and P-waves. The results show that the presence of backscattered R-waves and the changes in the R-wave velocity spectrum can help in cavity identification. Additional possible evidence is represented by significant changes in the refraction travel times over the cavity location. It can be concluded that the field data are in good agreement with the synthetic, and it could be effective to consider the results of both R- and P-wave analysis in order to efficiently identify the cavities.

污水坑和洞室可能对人类安全和城市基础设施构成严重危害，导致路基沉陷等。因此，必须评估不同深度和尺寸的各种下沉坑，以评估坍塌的风险。本文评估了不同腔对瑞利波传播和体波的影响。瑞利（R）波传播是根据表面波的经典多通道分析（MASW）方法进行分析的，同时考虑了R波的反向散射。通过有限元建模（FEM）计算出不同深度和尺寸的腔体和侵入体的合成地震道。此外，现场采集数据用于验证腔对R和P波的检测效果。结果表明，反向散射R波的存在和R波速度谱的变化可以帮助识别腔体。其他可能的证据以整个腔位置上的折射传播时间的显着变化表示。可以得出结论，现场数据与合成数据非常吻合，考虑R波和P波分析的结果以有效识别空洞可能是有效的。