Microtremors were measured at 18 stations to the west of Riyadh, and the H/V spectral ratio method was used to estimate the resonance frequency and amplification factor. These parameters indicate the presence of foundation bedrocks at various levels with variable thickness of soil where resonance frequency varies from 0.26 to 2.63 Hz, while the amplification factor ranges from 1.1 to 8.9. Moreover, four seismic refraction profiles have been carried out and illustrated two layers: the first of which has a P-wave velocity of 2000 m/s and a thickness of 1.5 m, whereas the second layer is characterized by P-wave velocity from 4010 to 4274 m/s. Besides, four multichannel analyses of surface wave (MASW) profiles have been conducted along the same refraction profiles to estimate the shear wave velocities along these profiles. The constructed 1D and 2D models indicate shear wave velocity ranges from 400 m/s to more than 4000 m/s with horizontal and vertical variation through the investigated area. Furthermore, the dynamic properties of rock and soil materials including Poisson’s ratio, Young’s modulus, shear modulus, material index, concentration index and ultimate bearing capacity have been calculated based on P- and S-wave velocities. These properties reveal less competent to competent material scales. Subsurface karst cavities have been detected in the study area at different depths and various dimensions. It is highly recommended that preventive measures including probing drilling to anticipate karst cavities below the designed foundations must be applied before construction of new engineering facilities in the study area. Otherwise, it will be geotechnical problems in the future.

在利雅得以西的18个站点测量了微震，并使用H / V频谱比方法估算了共振频率和放大因子。这些参数表明在不同厚度的土壤中存在着不同水平的基础基岩，共振频率在0.26到2.63 Hz之间变化，而放大系数在1.1到8.9之间。此外，已进行了四个地震折射剖面图并显示了两层：第一层的P波速度为2000 m / s，厚度为1.5 m，而第二层的特征是从4010年开始的P波速度至4274 m / s。此外，已经沿着相同的折射剖面对表面波（MASW）剖面进行了四次多通道分析，以估算沿这些剖面的剪切波速度。所建立的一维和二维模型表明，横波速度范围从400 m / s到4000 m / s以上，并且在整个研究区域内水平和垂直方向都有变化。此外，基于P波和S波速度，计算了岩石和土壤材料的动力学特性，包括泊松比，杨氏模量，剪切模量，材料指数，浓度指数和极限承载力。这些特性表明，胜任胜任的材料标尺。在研究区域中，在不同深度和不同尺寸下都发现了地下​​岩溶洞穴。强烈建议在研究区域内建造新的工程设施之前，必须采取预防措施，包括探测钻探以预测岩溶腔是否低于设计的地基。否则，