气候变化领域集成服务门户(CCPortal): Detection of Gas Hydrates in Faults Using Azimuthal Seismic Velocity Analysis, Vestnesa Ridge, W-Svalbard Margin

CCPortal

DOI	10.1029/2019JB017949
	Detection of Gas Hydrates in Faults Using Azimuthal Seismic Velocity Analysis, Vestnesa Ridge, W-Svalbard Margin
	Singhroha S.; Bünz S.; Plaza-Faverola A.; Chand S.
发表日期	2020
ISSN	21699313
卷号	125 期号:2
英文摘要	Joint analysis of electrical resistivity and seismic velocity data is primarily used to detect the presence of gas hydrate-filled faults and fractures. In this study, we present a novel approach to infer the occurrence of structurally controlled gas hydrate accumulations using azimuthal seismic velocity analysis. We perform this analysis using ocean-bottom seismic data at two sites on Vestnesa Ridge, W-Svalbard Margin. Previous geophysical studies inferred the presence of gas hydrates at shallow depths (up to ~190–195 m below the seafloor) in marine sediments of Vestnesa Ridge. We analyze azimuthal P-wave seismic velocities in relation with steeply dipping near-surface faults to study structural controls on gas hydrate distribution. This unique analysis documents directional changes in seismic velocities along and across faults. P-wave velocities are elevated and reduced by ~0.06–0.08 km/s in azimuths where the raypath plane lies along the fault plane in the gas hydrate stability zone (GHSZ) and below the base of the GHSZ, respectively. The resulting velocities can be explained with the presence of gas hydrate- and free gas-filled faults above and below the base of the GHSZ, respectively. Moreover, the occurrence of elevated and reduced (>0.05 km/s) seismic velocities in groups of azimuths bounded by faults suggests compartmentalization of gas hydrates and free gas by fault planes. Results from gas hydrate saturation modeling suggest that these observed changes in seismic velocities with azimuth can be due to gas hydrate saturated faults of thickness greater than 20 cm and considerably smaller than 300 cm. © 2020. The Authors.
英文关键词	azimuthal velocity analysis; gas hydrates; ocean bottom seismic (OBS); P-wave velocity modeling; travel time inversion; Vestnesa Ridge
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187946
作者单位	CAGE–Centre for Arctic Gas Hydrate, Environment and Climate, Department of Geosciences, UiT The Arctic University of Norway, Tromsø, Norway; Geological Survey of Norway (NGU), Trondheim, Norway
推荐引用方式 GB/T 7714	Singhroha S.,Bünz S.,Plaza-Faverola A.,et al. Detection of Gas Hydrates in Faults Using Azimuthal Seismic Velocity Analysis, Vestnesa Ridge, W-Svalbard Margin[J],2020,125(2).
APA	Singhroha S.,Bünz S.,Plaza-Faverola A.,&Chand S..(2020).Detection of Gas Hydrates in Faults Using Azimuthal Seismic Velocity Analysis, Vestnesa Ridge, W-Svalbard Margin.Journal of Geophysical Research: Solid Earth,125(2).
MLA	Singhroha S.,et al."Detection of Gas Hydrates in Faults Using Azimuthal Seismic Velocity Analysis, Vestnesa Ridge, W-Svalbard Margin".Journal of Geophysical Research: Solid Earth 125.2(2020).