地质力学学报2025，Vol.31Issue(1)：109-123,15.DOI:10.12090/j.issn.1006-6616.2024055
基于微动方法提高浅层横波波速结构反演精度——以海口江东新区为例
Improving the inversion accuracy of shallow shear wave velocity structure based on microtremor method:A case study of Haikou Jiangdong New District
摘要
Abstract
[Objective]The microtremor survey method is not limited by the spatiotemporal distribution of seismic sources and has become an effective method for observing the structure of shallow shear wave velocity.An experiment to compare microtremor,drilling,and shear wave logging was conducted in Jiangdong New District.The experiment showed that the microtremor inversion results were consistent with the logging curve shape,and the shear wave velocities of the strata and the corresponding depths were basically in agreement.Thus,good application results can be achieved.However,it was found that the microtremor inversion strata and the drilled strata did not completely correspond.In terms of wave velocity,the microtremor results could not reveal an interface with a small difference in wave velocity,while the drilling data did not distinguish an interface with a large difference in wave velocity.The study of the influence mechanism of the two factors on the microtremor inversion results is helpful to improve the understanding of the microtremor inversion model and to obtain more reasonable inversion results.[Methods]On the basis of a small or a large wave velocity difference,a physical stratification model,a geological stratification model,and a combined model are designed.The factors and rules affecting the inversion results are discussed by dispersion curves,low-velocity layers,layer variations,and inversion method.[Results]The inversion results of the physical property stratification model can better reflect the location of a weak layer.Changing the interface mainly affects the adjacent layers.Adding interfaces with small and large differences in wave velocity increases and decreases the wave velocity errors of the adjacent layers,respectively.The interface with a large velocity difference has less influence on the velocity of the adjacent layers than an interface with a small velocity difference.A large error change is mainly caused by an interface with a small velocity difference,and the inversion is more sensitive to an interface with a small velocity difference.[Conclusion]The practical application of the microtremor method in Jiangdong New District of Haikou shows that it is helpful to improve the inversion accuracy of the wave velocity by merging the interfaces with smaller wave velocity differences or adding interfaces with larger wave velocity differences,without changing the local trend of the layer velocity.[Significance]The 2D microtremor shear wave velocity section was obtained by inverting the measured data.Combined with the depth and undulation information of the bedrock surface provided by drilling,it provides a reliable basis for the site condition evaluation and the underground space utilization planning of Haikou Jiangdong New District.关键词
横波速度结构/波速差异界面/反演模型/微动方法Key words
shear wave velocity structure/wave velocity difference interface/inversion model/microtremor method分类
地球科学引用本文复制引用
张前,吴小洁,钟宙灿,蔡水库..基于微动方法提高浅层横波波速结构反演精度——以海口江东新区为例[J].地质力学学报,2025,31(1):109-123,15.基金项目
海南省海洋地质资源与环境重点实验室自主课题(22-HNHYDZZYHJKF023,HNHYDZZYHJZZ003) This research is financially supported by Key Laboratory of Marine Geological Resources and Environment of Hainan Province(Grants No.22-HNHYDZZ-YHJKF023 and HNHYDZZYHJZZ003). （22-HNHYDZZYHJKF023,HNHYDZZYHJZZ003）
