Journal of Tropical Oceanography ›› 2022, Vol. 41 ›› Issue (1): 184-193.doi: 10.11978/2020148CSTR: 32234.14.2020148

• Marine Geophysics • Previous Articles     Next Articles

Shallow geological structure in the Qiongbei volcanic area by using H/V method

CAO Jiajun1,5(), GUO Zhen2, XIA Shaohong1,3,4(), ZHANG Changrong1,3,4, WU Xiaoyang2, REN Pengfei2   

  1. 1. Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou 510301, China
    2. Department of Ocean Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
    3. Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 511458, China
    4. Sanya Institute of Oceanology, South China Sea Institute of Oceanology, Sanya 572022, China
    5. University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2020-12-07 Revised:2021-03-03 Online:2022-01-10 Published:2021-03-06
  • Contact: XIA Shaohong E-mail:caojiajun18@mails.ucas.ac.cn;shxia@scsio.ac.cn
  • Supported by:
    National Natural Science Foundation of China(42076071);National Natural Science Foundation of China(U1701641);Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou)(GML2019ZD0204);Guangdong Key Project(2019BT02H594);Hainan Key Research and Development Project(ZDYF2020198)

Abstract:

The Hainan Qiongbei volcanic area is a typical Quaternary volcanic area in the coastal area of South China, which has attracted worldwide attention. Previous studies focused more on deep geological structures and the evolution of this volcano, but its surface geological structure is not yet well understood. Horizontal-to-vertical (H/V) spectrum of microtremors has been widely applied to shallow subsurface structures. By using classic full wave field H/V(full) and the Rayleigh wave ellipticity H/V(Ray) methods, we obtained spatial variation of peak frequency (F0) and the amplification (A0) from a seismic array of 35 short-period seismometers in the Qiongbei volcanic area. The results show that the peak frequency of the H/V curve in the Qiongbei volcanic area is significantly different on both sides of the Changliu-Xiangou fault. Clear F0 and A0 can be found at every site on the northeast side of the fault, while they do not exist on the opposite side of the fault. Based on the existing geological data, we believe that the shallow volcanic rocks at the southwest side of the Changliu-Xiangou fault have not undergone significant weathering under the condition of geological depression background, while the northeast side of the fault is located in an uplift area, so the rocks have been weathered seriously. Our results show that the H/V method can be used to evaluate the weathering state of surface volcanic rocks, and the peak frequency and amplification factor of the H/V curve of the outcropping site of the volcanic rocks are more obvious with the increasing of the degree of weathering. Our study provides important information for the weathering state of the volcanic rocks in the shallow and seismic risk assessment of this area.

Key words: H/V method, Qiongbei volcanic area, ambient noise, shallow geological structure

CLC Number: 

  • P712.83