Long-term Observations on Gas Venting off Vancouver Island from Ocean Networks Canada's NEPTUNE Observatory
Abstract
Gas discharge on the Cascadia Margin off Vancouver Island is observed with a permanent seafloor sonar since 2012. We show the emission variability over time with the most prominent correlation of emissions with tides as well as longer-term periods of lower and higher emissions. The control mechanism of these naturally varying phases of emissions is unknown, and we welcome feedback on what could potentially contribute to this long-term cycle.
This dataset has been acquired through Ocean Networks Canada's seafloor cabled observatory called NEPTUNE off the coast of Vancouver Island, with one of the five instrumented science nodes on the gas hydrate site Clayoquot Slope near the well-studied Bullseye Vent. The observatory enables power and communication to the seafloor in near-real time, and thus colocation of many instruments whose data can be correlated with the sonar data. Among the additional data sets are seismometer data for ground shaking, CTD for salinity, temperature and pressure, tilt-meter for subtle seafloor deformation, current meters for water speeds. Gas discharge has been mapped and quantified along the entire Cascadia Margin over many years of ship expeditions, and the long-term observations from a single site help assess the extrapolation of margin-wide single-instance observation to fully understand natural gas venting from the seabed. All Ocean Networks Canada data are freely and openly accessible through https://data.oceannetworks.ca.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMOS43B1705S
- Keywords:
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- 3002 Continental shelf and slope processes;
- MARINE GEOLOGY AND GEOPHYSICS;
- 3004 Gas and hydrate systems;
- MARINE GEOLOGY AND GEOPHYSICS;
- 3045 Seafloor morphology;
- geology;
- and geophysics;
- MARINE GEOLOGY AND GEOPHYSICS;
- 3050 Ocean observatories and experiments;
- MARINE GEOLOGY AND GEOPHYSICS