Velocity structure of sedimentary formation in the South Yellow Sea Basin based on OBS data

doi:10.6038/cjg2018L0623

IOCAS-IR > 海洋地质与环境重点实验室

	Velocity structure of sedimentary formation in the South Yellow Sea Basin based on OBS data
	Zhao WeiNa 1,2,3; Zhang XunHua 4; Zou ZhiHui 5; Wu ZhiQiang 6; Hao TianYao 7; Zheng YanPeng 8,9; Liu Kai 8,9
	2019
发表期刊	CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION
ISSN	0001-5733
卷号	62 期号:1 页码:183-196
通讯作者	Wu ZhiQiang(wuzq_1964@163.com)
摘要	After many years of geological and geophysical studies, the South Yellow Sea (SYS) is believed to be the front of South China Block when colliding with the North China Block. The SYS basin is filled by the Mesozoic-Cenozoic terrigenous sediments overlying the Pre-Paleozoic and Mesozoic-Paleozoic marine sediments. As the results of the multi-stage tectonic activity and sedimentation events, the SYS basin has very complex structure. Many geophysical surveys have been conducted to uncover the detailed basin structures. However, the connection of the shallow and deep structures remain to be studied, either due to the low resolution of crustal structure for the magnetic and gravity methods or due to the lack of deep structure information in the shortoffset marine seismic data. Here, we use the first-arrival time data of a wide-angle OBS array (OBS2013) and the multiscale seismic tomography (MST) to invert the P-wave velocity structure of the SYS. The MST method is devised to cope with the poor determinacy caused by the uneven raypaths coverage. By decomposing the inverted area with the sub-models with different cell sizes, the MST method can invert the velocity model on the meshes with correct scale and provide a smoother velocity model that is suitable for the geologic interpretation. The accuracy of the first-arrival times is improved after adopting a five-station moving average method, which suppresses the random noise and enhances the first-arrival waveforms by averaging the nearby traces. The selection of data is based on the angle between the array and the shot-receiver line. Here, the picks with angle less than two degrees are adopted to avoid the off-line influence. To show the resolution of our MST algorithm, we conducted a checker-board test using the same inversion parameters and shotreceiver geometry with the case of field-data inversion. The resulted velocity profile shows that the velocity anomalies shallower than 6 km depth is properly recovered. By comparing the inverted velocity model with multi-channel seismic profile, the sedimentary formation is interpreted, referring to gravity and magnetic data. The final inverted velocity model shows strong lateral and vertical velocity variations. In the vertical, the sedimentary formation is divided into two parts by the Indosinian surface. The top one is the extensional formation with low P-wave velocity, and the other is the extrusion formation carrying a high speed feature. In the transverse, six boundaries of lateral velocity (F1-F6) were interpreted as six faults, which control the development of the SYS basin. Based on the research results, we infer F1 to be the boundary of Jiaolai basin and F4 to be a strike-slip fault, which is a normal fault on its top and the reverse fault at its bottom. The faults divide the sedimentary formation beneath the survey line into low or high P-wave velocity zones. Four low velocity zones (LVZs, <4. 5 km . s (1)) and five high velocity zones (HVZs, >5 km . s (1)) are identified beneath 2013OBS line with the prior gravity, magnetic and conventional seismic data. The LVZs, namely I, II, III and IV, have the similar gravity and magnetic anomaly characteristics, and are demonstrated to be formed in the faulted period. In the HVZs, area V consists of the metamorphic rocks formed during the collision orogeny in the Qianliyan Uplift. The other four HVZs show as high-value gravity anomaly and low-value magnetic anomaly in the Northern Depression, which correlate with the feature of the marine sedimentary strata. However, sandstone is confirmed located at the strata with 2 km thickness in VIII and IX (buried depth <6 km) with a lower velocity (5 km . s P-wave), referring to the V-P/V-S. Based on the short wavelength magnetic anomaly, there might be igneous rocks in the HVZ IX of the Central Uplift.
关键词	South Yellow Sea OBS Multi-scale seismic tomography Velocity of sedimentary formation
DOI	10.6038/cjg2018L0623
收录类别	SCI
语种	英语
WOS研究方向	Geochemistry & Geophysics
WOS类目	Geochemistry & Geophysics
WOS记录号	WOS:000457640700014
出版者	SCIENCE PRESS
引用统计	被引频次：6[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://ir.qdio.ac.cn/handle/337002/160841
专题	海洋地质与环境重点实验室
通讯作者	Wu ZhiQiang
作者单位	1.Guangdong Ocean Univ, Guangdong Prov Key Lab Coastal Ocean Variat & Dis, Zhanjiang 524088, Peoples R China 2.Chinese Acad Sci, Inst Oceanol, Key Lab Marine Geol & Environm, Qingdao 266071, Peoples R China 3.Northwestern Polytech Univ, Qingdao Res Inst, Qingdao 266200, Peoples R China 4.China Geol Survey, Nanjing Ctr, Nanjing 210016, Jiangsu, Peoples R China 5.Ocean Univ China, Coll Marine Geosci, Qingdao 266100, Peoples R China 6.Qingdao Inst Marine Geol, Qingdao 266071, Peoples R China 7.Chinese Acad Sci, Inst Geol & Geophys, Beijing 100029, Peoples R China 8.Minist Nat Resources, Inst Oceanog 1, Key Lab Marine Sedimentol & Environm Geol, Qingdao 266061, Peoples R China 9.Qingdao Natl Lab Marine Sci & Technol, Lab Marine Geol, Qingdao 266061, Peoples R China
第一作者单位	中国科学院海洋研究所
推荐引用方式 GB/T 7714	Zhao WeiNa,Zhang XunHua,Zou ZhiHui,et al. Velocity structure of sedimentary formation in the South Yellow Sea Basin based on OBS data[J]. CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION,2019,62(1):183-196.
APA	Zhao WeiNa.,Zhang XunHua.,Zou ZhiHui.,Wu ZhiQiang.,Hao TianYao.,...&Liu Kai.(2019).Velocity structure of sedimentary formation in the South Yellow Sea Basin based on OBS data.CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION,62(1),183-196.
MLA	Zhao WeiNa,et al."Velocity structure of sedimentary formation in the South Yellow Sea Basin based on OBS data".CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION 62.1(2019):183-196.