Marine gas hydrates, fluid flow, and structure at convergent margins

甲烷水合物是在水深大于600米的大陆斜坡上发现的“可燃冰”。水合物储藏库中包含的甲烷数量巨大。因此，水合物是一种巨大的潜在能源资源，并可能在控制全球气候和海底塌陷方面发挥重要作用。我研究的一个主要重点是确定温哥华岛外甲烷水合物的分布和浓度，并随后了解它们是如何形成的。我的大部分工作将与综合海洋钻探计划(IODP)的成果联系在一起，该计划目前在温哥华岛附近进行钻探(2005年10月)。我的研究活动将包括分析2005年8月在海底地震仪(OBSS)上收集的海洋地震数据。我将检查地震走时和振幅，以确定IODP计划两个主要地点的地震速度结构；IODP结果将校准地震模型，然后提供距离钻孔1-2公里的水合物分布估计。OBS计划于2007年进行一次更大规模的地震调查，调查范围为5公里乘2公里，其中包括几个流体喷口特征，在那里就在海底下方发现了大量水合物。这艘邮轮与南安普顿大学和多伦多大学合作，其一个独特的特点是，将使用可控源电磁设备在相同体积上收集海底电阻率的测量结果。有了电阻率和地震速度，水合物浓度的估计可能会有很大改进。第三项现场调查暂定于2008年进行，是一项OBS项目，重点是温哥华岛外努特卡断裂带的流体喷口结构，该断裂带位于大陆斜坡的海边。有关这些构造的信息可能会为未来的IODP钻探提供支持。由于努特卡断层上发生了许多地震，对钻孔(可能是海王星光纤网络的一个节点)的持续监测可能表明，喷口活动可能与地震有直接联系。

Methane hydrate is "flammable ice" found on continental slopes where water depths are greater than about 600 m. The amount of methane contained in the hydrate reservoir is enormous. Hydrates thus represent a massive potential energy resource, as well as possibly playing a major role in controlling global climate and seafloor slumping. A major focus of my research is to determine the distribution and concentration of methane hydrate off Vancouver Island, and subsequently to understand how they are formed. Much of my work will be linked to results from the Integrated Ocean Drilling Program (IODP), currently drilling (Oct 2005) off Vancouver Island. My research activities will include analysis of marine seismic data collected on ocean bottom seismometers (OBSs) in Aug 2005. I will examine seismic traveltimes and amplitudes to determine the seismic velocity structure at two of the major sites of the IODP program; the IODP results will calibrate the seismic models, which then provide estimates of hydrate distribution out to distances of 1-2 km away form the drillholes. A larger-scale OBS seismic survey is planned for 2007, over an area 5 km by 2 km that includes several fluid vent features where massive hydrate has been recovered just below the seafloor. A unique feature of this cruise, which is in collaboration with the U of Southampton and the U of Toronto, is that measurements of seafloor resistivity will be collected over the same volume using controlled-source EM equipment. With both resistivity and seismic velocity, the estimates of hydrate concentration may be much improved. A third field survey, planned tentatively for 2008, is an OBS program focusing on fluid vent structures in the Nootka fault region off Vancouver Island, just seaward of the continental slope. Information on these structures may provide support for future IODP drilling here. Since many earthquakes occur on the Nootka fault, continuous monitoring of a drillhole (perhaps as a node of the NEPTUNE fibre-optic network) may demonstrate that vent activity may be directly linked to earthquakes.