The environmental threats of soil subsistence in Jeddah city have been assessed using cross-hole seismic testing. These threats affect the state of health of roads, buildings, near-surface foundations ensuring a reliable and economic infrastructure design, as unanticipated site conditions can cause significant traffic problems, soil subsidence, and structural collapse. Cross-hole seismic testing is of utmost importance in determining velocity profiles of P- and S-waves for environmental hazard assessment. These velocity profiles are required to calculate the geotechnical parameters of soil nearby important structures. A cross hole seismic survey was conducted at boreholes close to Jeddah desalination plant. A sledgehammer horizontally striking a wooden plate was used to generate S-waves polarized in the crossline and inline directions. A vertical hammer hitting a metal plate to generate the P-wave then the first break arrival times were inverted for the P- and S-wave velocity structure estimation. The equipment and procedures comply with the American Society for Testing and Materials (ASTM) D 4428/D 4428M-91 standard test method for cross-hole seismic testing. The estimated velocities were utilized to calculate the elastic moduli, geotechnical parameters and density variations within the mapped area. These parameters agree with the lithological variations of near- surface sediments from borehole logs. Finally, the study area illustrated soft, fractured, and poorly graded sediments, which, in turn, require special treatment from engineering point of view before establishing the important facilities in the area. These results are highly recommended and have to be considered to mitigate the environmental hazards in Jeddah city.

已使用跨孔地震测试评估了吉达市土壤生存的环境威胁。这些威胁影响道路，建筑物，近地表基础的健康状况，从而确保可靠和经济的基础设施设计，因为意外的场地条件可能会导致严重的交通问题，土壤沉降和结构倒塌。跨孔地震测试对于确定P波和S波的速度剖面以进行环境危害评估至关重要。需要这些速度剖面来计算重要结构附近土壤的岩土参数。在吉达海水淡化厂附近的井眼中进行了跨孔地震勘测。水平敲击木板的大锤被用来产生在交叉线和在线方向上极化的S波。垂直锤击中金属板以产生P波，然后反转第一次断裂的到达时间，以估计P波和S波的速度结构。该设备和程序符合美国测试和材料协会（ASTM）D 4428 / D 4428M-91标准的跨孔地震测试方法。估计的速度用于计算映射区域内的弹性模量，岩土参数和密度变化。这些参数与来自钻孔测井的近地表沉积物的岩性变化一致。最后，研究区域显示出柔软，破碎和分级不佳的沉积物，从工程学角度出发，在该区域建立重要设施之前，需要对其进行特殊处理。