2009/09/08
Labels: showcomments, sediment, thompson, ropos, deployment, installation, cable, seismometer, seismology, earthquake
On 8 September we successfully installed and tested the first of three broadband seismometers to be deployed this summer. Seismologist Bob Meldrum was aboard to oversee the installation, which was accomplished using the ROPOS zip pump. Our activities were also closely monitored by local residents, including squid, curious halibuts and some very nosy longnose skates.
Our Seismometers
Watertight cast titanium spheres contain a broadband seismometer and a strong motion accelerometer. They are placed on the seafloor within a heavy plastic caisson and buried in tiny glass beads.
Preparations |
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Rebar "staples" used to secure the seismometer cable to the seafloor.
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These glass beads, 0.5-0.7mm in diameter, are used to bury the seismometers within their caissons on the seafloor.
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NEPTUNE Canada contractor Jason Williams grinds a titanium bar forming part of the seismometer handle, 7 September 2009.
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Barkley Slope seismometer in its shipping box prior to deployment, 7 September 2009.
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(Click images to view slideshow.)
Excavation & Installation |
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The Barkley Slope seismometer sits within the caisson, parially buried in glass beads, 8 September 2009.
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ROPOS gently transports the seismometer with connecting cable, 8 September 2009.
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Clay tailings excavated from the caisson by the zip pump, 8 September 2009.
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The caisson was first pressed into the seafloor, then the sediment on the inside was vacuumed out using the ROPOS zip pump.
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Seismometer connecting hose is plugged into the extension cable, 8 September 2009.
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After placing the seismometer carefully into the caisson, we buried it in tiny glass beads. Several longnose skates (Raja rhina) were very interested in our operations.
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(Click images to view slideshow.)
Burial |
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The seismometer site after burial of the caisson and part of the connecting cable, 8 September 2009.
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The caisson is nearly full as glass bead bags #9 and #10 are emptied, 8 September 2009.
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ROPOS inserts 'staples' into the sediment to secure the seismometer cable as a halibut swims past, 8 September 2009.
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(Click images to view slideshow.)
Local Residents |
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This curious longnose skate (Raja rhina) sailed repeatedley around, over and through our worksite.
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Halibut makes puppy eyes, 8 September 2009.
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Squid frequent the instrument platform, which sits at a depth of 398m. Here, ROPOS is extending the seismometer connection hose.
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This curious halibut lay down just in front of ROPOS and spent a long while watching, 8 September 2009.
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These salp strands, observed at 118m, resemble Christmas lights.
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(Click images to view slideshow.)
Once installed, our network of seismometers will enable the same kind of research that takes place on land to take place within the NEPTUNE Canada footprint on the ocean floor. This includes studying earthquakes on the ridge due to tectonic, magmatic and hydrothermal processes, earthquakes on the offshore fracture zones, mid-plate earthquakes, and earthquakes within the oceanic plate as it begins to subduct and those in the region of the expected subduction megathrust event. Data flow from the NEPTUNE Canada Seismograph Network will be integrated in real time with the adjacent land based Canadian National Seismograph Network operated by the Geological Survey of Canada. To learn more about this project, see the related web page
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