A SEISMIC STUDY OF METHANE HYDRATE MARINE BOTTOM SIMULATING REFLECTORS
A SEISMIC STUDY OF METHANE HYDRATE MARINE BOTTOM SIMULATING REFLECTORS
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DOI：
10.1029/92jb00234
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发表时间：
1992-05-10
影响因子：
3.9
通讯作者：
SPENCE, GD
中科院分区：
文献类型：
--
作者：
HYNDMAN, RD;SPENCE, GD
对温哥华岛北部卡斯卡迪亚俯冲带边缘明底模拟反射区（BSRs）的多道地震反射数据进行了分析。在海底下约300米深处的反射器被解释为代表甲烷水合物或笼形物层的底部。1300米的浅水深度和3600米长的水听器阵列允许进行BSR振幅-偏移和高分辨率速度分析，以及垂直入射数据建模。这三种分析的结果都可以用一个10到30米厚的高速层来解释，该层位于BSR上方，位于海底以下约300米处，具有尖锐的底部和过渡顶部。在这一层中，大约三分之一的沉积物孔隙空间必须被水合物“冰”填满。在bsr下面没有地震探测到的游离气体。这些结果对BSR水合物的分布和形成模型提出了重要的约束。
Multichannel seismic reflection data have been analyzed from an area of clear bottom simulating reflectors (BSRs) on the northern Cascadia subduction zone margin off Vancouver Island. The reflector at a depth of about 300 m subbottom is interpreted to represent the base of a layer of methane hydrate or clathrate. The shallow water depth of 1300 m and the 3600-m-long hydrophone array have allowed BSR amplitude-versus-offset and high-resolution velocity analysis, as well as modelling of vertical incidence data. The results of all three types of analysis can be best explained by a 10 to 30-m-thick high-velocity layer located immediately above the BSR about 300 m below the seafloor, having a sharp base and transitional top. In the layer, about one third of the sediment pore spaces must be filled with hydrate "ice ". There is no seismically detectable free gas beneath the BSRs. These results put important constraints on models for the distribution and formation of BSR hydrate.