Improving the inversion accuracy of shallow shear wave velocity structure based on microtremor method: A case study of Haikou Jiangdong New District
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 Jiangdo...
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Institute of Geomechanics, Chinese Academy of Geological Sciences
2025-01-01
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| Series: | Dizhi lixue xuebao |
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| Online Access: | https://journal.geomech.ac.cn//article/doi/10.12090/j.issn.1006-6616.2024055 |
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| author | ZHANG Qian WU Xiaojie ZHONG Zhoucan CAI Shuiku |
| author_facet | ZHANG Qian WU Xiaojie ZHONG Zhoucan CAI Shuiku |
| author_sort | ZHANG Qian |
| collection | DOAJ |
| description | 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. |
| format | Article |
| id | doaj-art-a82c2c35922042f3b0e31530c12cee4f |
| institution | OA Journals |
| issn | 1006-6616 |
| language | zho |
| publishDate | 2025-01-01 |
| publisher | Institute of Geomechanics, Chinese Academy of Geological Sciences |
| record_format | Article |
| series | Dizhi lixue xuebao |
| spelling | doaj-art-a82c2c35922042f3b0e31530c12cee4f2025-08-20T01:51:13ZzhoInstitute of Geomechanics, Chinese Academy of Geological SciencesDizhi lixue xuebao1006-66162025-01-0131110912310.12090/j.issn.1006-6616.2024055Improving the inversion accuracy of shallow shear wave velocity structure based on microtremor method: A case study of Haikou Jiangdong New DistrictZHANG QianWU XiaojieZHONG ZhoucanCAI ShuikuObjective 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.https://journal.geomech.ac.cn//article/doi/10.12090/j.issn.1006-6616.2024055shear wave velocity structurewave velocity difference interfaceinversion modelmicrotremor method |
| spellingShingle | ZHANG Qian WU Xiaojie ZHONG Zhoucan CAI Shuiku Improving the inversion accuracy of shallow shear wave velocity structure based on microtremor method: A case study of Haikou Jiangdong New District Dizhi lixue xuebao shear wave velocity structure wave velocity difference interface inversion model microtremor method |
| title | Improving the inversion accuracy of shallow shear wave velocity structure based on microtremor method: A case study of Haikou Jiangdong New District |
| title_full | Improving the inversion accuracy of shallow shear wave velocity structure based on microtremor method: A case study of Haikou Jiangdong New District |
| title_fullStr | Improving the inversion accuracy of shallow shear wave velocity structure based on microtremor method: A case study of Haikou Jiangdong New District |
| title_full_unstemmed | Improving the inversion accuracy of shallow shear wave velocity structure based on microtremor method: A case study of Haikou Jiangdong New District |
| title_short | Improving the inversion accuracy of shallow shear wave velocity structure based on microtremor method: A case study of Haikou Jiangdong New District |
| title_sort | improving the inversion accuracy of shallow shear wave velocity structure based on microtremor method a case study of haikou jiangdong new district |
| topic | shear wave velocity structure wave velocity difference interface inversion model microtremor method |
| url | https://journal.geomech.ac.cn//article/doi/10.12090/j.issn.1006-6616.2024055 |
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