Application of Microtremor Exploration in Loess Strata Division

[Purposes] During the deposition process, loess is significantly influenced by climatic conditions, exhibiting distinct layering alternations between loess and paleosols. Its physical and mechanical properties also vary notably, providing favorable geophysical conditions for microtremor exploration of loess layers. [Methods] To validate the reliability and accuracy of microtremor exploration in loess layers division, experimental studies were conducted near the standard loess profile in Potou Village, Luochuan, and on Shaoling Yuan in Xi’an. [Results] The study results indicate that geological stratification of loess can be achieved according to changes in the inflection points and slopes of the dispersion curves derived from seismic velocity-depth profiles, as well as variations in the density of dispersion points. The accuracy of stratification is notably affected by the number of points on the dispersion curve. For shallow loess layers, stratification should employ dispersion curves corresponding to 512 and 1 024 sample points, while for deeper loess layers, those corresponding to 2 048 sample points are recommended. The difference in layer depths between those determined by borehole and microtremor explorations is less than 0.6 m.