High resolution structure of Hualong fault revealed by ambient noise double beamforming imaging with dense seismic array 密集台阵背景噪声双聚束成像化龙断裂精细结构

Wu，Xiaoyang1,2; Tan，Junqing1,2; Guo，Zhen2,4,5; Ren，Pengfei2; Wang，Liwei3; Ye，Xiuwei3; Chen，Yongshun2,4,5

2022-05-10

10.6038/cjg2022P0549

CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION   影响因子和分区

0001-5733

Double beamforming tomography (abbreviated as DBF) is a new method to image underground velocity structure using seismic ambient noise records. DBF can improve the signal-to-noise ratio by superposing the coherent energy of ambient noise field, which is helpful to identify and extract different types of seismic waves and their incident azimuth (weak body wave, reflected surface wave, etc.), so as to conduct imaging research on underground velocity structure. Particularly for ambient noise surface wave imaging, DBF does not require tomographic inversion, as it ensures directly finding the appropriate phase velocities from local slowness (azimuthal) searching. With a dense seismic nodal array, we image the shallow structure of Hualong fault in Panyu, Guangzhou based on ambient noise records. Fundamental Rayleigh wave phase velocities are extracted for periods of 0.6~1.2 s using DBF method. Then, a 2-D V profile model from the surface to 1200 m depth is derived by shear wave inversion. V results show that the shallow low-velocity anomalies in the northeast side of the array (near the Pearl River Delta) extend to the depth of 600 m, reflecting differences in sediment thickness, compaction rate and lithologic composition in different blocks on both sides of Hualong fault. In addition, the relative high-velocity anomalies below depth of 900 m correspond to the bedrock formed by Tertiary magmatic activities. The near-surface structural characteristics of Hualong fault effectively improve our cognition of the fault system in the Pearl River Delta, which also provide valuable references for further studies on regional structural characteristics, focal mechanisms and seismic hazard assessment.

Ambient noise Double beamforming tomography Hualong fault Shear wave velocity

SCI ; EI

中文

通讯

Geochemistry & Geophysics

Geochemistry & Geophysics

WOS:000796746600012

SCIENCE PRESS

20221912084073

Beamforming ; Phase velocity ; Seismic waves ; Seismology ; Shear flow ; Shear waves ; Signal to noise ratio ; Surface waves ; Tomography ; Velocity

Seismology:484 ; Earthquake Measurements and Analysis:484.1 ; Fluid Flow, General:631.1 ; Electromagnetic Waves in Different Media:711.1 ; Electromagnetic Waves in Relation to Various Structures:711.2 ; Information Theory and Signal Processing:716.1 ; Imaging Techniques:746 ; Acoustic Noise:751.4 ; Mechanics:931.1

GEOSCIENCES

2-s2.0-85129550031

Scopus

1.Harbin Institute of Technology,Harbin,150000,China
2.Department of Ocean Science and Engineering,Southern University of Science and Technology,Shenzhen,518055,China
3.Guangdong Earthquake Agency,Guangzhou,510070,China
4.Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou),Shenzhen Branch,Guangzhou,511458,China
5.Shanghai Sheshan National Geophysical Observatory,Shanghai,201602,China

Wu，Xiaoyang,Tan，Junqing,Guo，Zhen,等. High resolution structure of Hualong fault revealed by ambient noise double beamforming imaging with dense seismic array 密集台阵背景噪声双聚束成像化龙断裂精细结构[J]. CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION,2022,65(5):1701-1711.

Wu，Xiaoyang.,Tan，Junqing.,Guo，Zhen.,Ren，Pengfei.,Wang，Liwei.,...&Chen，Yongshun.(2022).High resolution structure of Hualong fault revealed by ambient noise double beamforming imaging with dense seismic array 密集台阵背景噪声双聚束成像化龙断裂精细结构.CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION,65(5),1701-1711.

Wu，Xiaoyang,et al."High resolution structure of Hualong fault revealed by ambient noise double beamforming imaging with dense seismic array 密集台阵背景噪声双聚束成像化龙断裂精细结构".CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION 65.5(2022):1701-1711.