Collaborative Research: Acoustic Instrumentation for Imaging and Quantifying Hydrothermal Flow in NEPTUNE Canada Regional Cabled Observatory at Main Endeavour Field, JdFR

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The PI's request funding to develop and connect sonar instrumentation to monitor hydrothermal flow at the NEPTUNE Canada Regional Cabled Observatory (RCO) in the Main Endeavour Field (MEF) on the Juan de Fuca Ridge (JdFR) offshore British Columbia as part of the Ocean Observatories Initiative (OOI). The backbone cable for this RCO was installed in 2007 and the nodes and junction boxes are scheduled for installation in 2009. The proposed instrumentation will acoustically image time series of the changing 3D geometry, flow rate and volume flux of buoyant plumes discharging from vents and areal distribution of diffuse flow from the surrounding seafloor. Connection to NEPTUNE Canada will provide the power and bandwidth to extend our present technically proven capability of imaging from days/weeks (ROV or battery power) to months/years. This temporal extension will enable monitoring of fluxes of hydrothermal flow and detecting linkages with external forcing processes from tidal cycles to geologic events (earthquakes, volcanic activity). The proposed new instrumentation, the Cabled Observatory Imaging Sonar System (COVIS), is designed as an ideal instrument for the power and data bandwidth afforded by the cabled observatory and will adapt to NEPTUNE Canada Stage I mechanical, electrical, and software functional requirements. A state-of-the-art commercial off-the-shelf sonar (400 kHz) will be acquired and integrated onto a custom benthic tripod lander with a central tower and angular translation system. The 3-axis angular translation system will allow operators to precisely position the multi-beam sonar head into observing positions for both plume and diffuse flow measurements, will be adaptable to changes of the flow orientations, will be capable of autonomous response to significant geophysical events detected by other NEPTUNE Canada instrumentation via shore based control software, and will have scope to be moved within the vent field. Broader Impacts: This work should enable a real-time window to seafloor hydrothermal flow and its interaction with oceanic and geological processes. The great public awareness and educational impacts this installation could have for the general public and K-12 through college education/inspiration are obvious and should be encouraged. There may be some thesis benefits for engineering graduate students, as well.