Application of ambient noise tomography to coastal granite islands: A case study of Wuzhizhou Island in Hainan, China
Huang Cheng, Liu Sheng*, Long Jun-Qiao, Zhang Chang-Rong, Xiao Bo, Wang Da-Cheng,
Wei Cheng-Long, Wang Rui, Yan Li, Hu Xuan, Xin Zhuo, Meng Xiu-Ji, Xing Jing-Feng
1. Haikou Marine Geological Survey Center, China Geological Survey, Haikou 571127, China;
2. Ocean University of China, Qingdao 266100, China;
3. South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China;
4. Hainan University, Haikou 570228, China
Abstract：
Islands are valuable land resources in the ocean, and their detailed subsurface seismic velocity structures are highly important for underground space utilization, engineering construction, and geological disaster prevention. Ambient noise tomography and the horizontal–vertical spectral ratio (HVSR) method use ambient noise recordings instead of earthquake signals to study the underground velocity structure, making them easy to implement on islands and consequently becoming potential optimization schemes for the investigation of detailed island structures. However, the application of these technologies to small granite islands along coasts is relatively insufficient, and the applicability needs to be further verified. This study ambient noise tomography and HVSR analysis were carried out by using a dense array of seismic data on Wuzhizhou Island, Hainan. It was found that natural activities mainly cause the ambient noise below 8 Hz on Wuzhizhou Island. Moreover, high-quality noise cross-correlation functions of 3–8 Hz can be extracted. The results of ambient noise tomography and HVSR analysis show that the underground S-wave velocity structure and sedimentary characteristics of Wuzhizhou Island are coupled with its topography. The high-terrain area of Wuzhizhou Island exhibits low-velocity anomalies, where a sedimentary layer did not develop. On the other hand, the low-terrain area of Wuzhizhou Island exhibits high-velocity anomalies, where a thin Quaternary sedimentary layer developed. These results imply that subsurface magmatic activity controls the island topography and aff ects the distribution of the island sedimentary layer. This study successfully verifi es the feasibility of detection methods based on ambient noise in small granite islands along the coast. It also provides key basic information for studying the geological evolutionary history, island spatial planning, and geological disaster prevention of Wuzhizhou Island.
基金资助:This work was supported by the geological survey project (Grant No. DD20220992; Grant No. DD20242841; Grant No.DD20230592 and Grant No. DD20220993) ; Innovation Foundation of Science and Technology for “Nanhai New Star”Projects (Grant No. NHXXRCXM202353 ) of Hainan province.
作者简介: Huang Cheng, Senior engineer, received a Master 's degree in Mineralogy, Petrology and Mineral Deposits from China University of Geosciences ( Beijing ) in 2014. From 2020 to 2024, he studied as an in-service doctoral student at Ocean University of China.At present, he works in Haikou Marine Geological Survey Center of China Geological Survey, mainly engaged in the investigation and research of marine basic geology, marine resources and environment, island geology and so on.
. Application of ambient noise tomography to coastal granite islands: A case study of Wuzhizhou Island in Hainan, China[J]. APPLIED GEOPHYSICS, 2025, 22(4): 1326-1340.
2025, Vol. 22 
