All posts by William Hanshumaker

2012 - R/V New Horizon, Missions, Procedures, Recovery, Seismometers, SIO

Friday the 13th – First night at sea

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Aboard the New Horizon

Departed the NOAA’s MOC-P dock at approximately 16oo hours. The weather was clear with ocean swells coming in from the Northwest.

The fifteen instruments to be recovered were some of those that were deployed from the October voyage of the Wecoma. These are the Scripps Institute of Oceanography “Abalones”.  Abalones are trawl-resistant, three component, battery powered ocean bottom seismometers, capable of being deployed in water depths of 50 to 6000 meters. We are recovering them via an acoustic release. After cruising to the proper latitude and longitude, an acoustic signal is sent down from the ship to “wake up” the Abalone. The Abalone acknowledges by sending back its own acoustic signal. We then send another acoustic signal down to the  burn wire. The burn wire is an alloy of nickel and chromium. When an electric current is passed through it, the burn wire begins to oxidize. After about seven and a half minutes, the Abalone separates from its steel ballast and floats to the surface at about 60 meters per minute.

The first Abalone slated for recovery had been deployed in 1356 meters of water. After its 22-minute ascent, the strobe from the first Abalone was sighted at 22:05. The rough seas and high wind complicated recovery.  The deck crew missed the first pass, and the New Horizon had a difficult time keeping the floating Abalone along its starboard side. Eventually we secured our first recovery to the deck at 22:45.

We will cruse through the night to our second station.

2012 - R/V New Horizon, Recovery, Seismometers

Friday the 13th – First night at sea

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The fifteen instruments to be recovered were some of those that were deployed from the October voyage of the Wecoma. These are the Scripps Institute of Oceanography “Abalones”. Abalones are trawl-resistant, three component, battery powered ocean bottom seismometers, capable of being deployed in water depths of 50 to 6000 meters. We are recovering them via an acoustic release. After cruising to the proper latitude and longitude, an acoustic signal is sent down from the ship to “wake up” the Abalone’s acoustic release. The Abalone acknowledges by sending back its own acoustic signal. We then send a signal down to the acoustic release burn wire. The burn wire is an alloy of nickel and chromium. When an electric current is passed through it, the burn wire begins to oxidize. After about seven and a half minutes, the Abalone separates from its steel ballast and floats to the surface at about 60 meters per minute.

The first Abalone slated for recovery (Y1M7) was deployed in 1356 meters of water. After its 22-minute ascent, the strobe from the first Abalone was sighted at 22:05. The rough seas and high wind complicated recovery.  The deck crew missed the first pass, and the New Horizon had a difficult time keeping the floating Abalone along its starboard side. Eventually we secured our first recovery to the deck at 22:45.

We will cruse through the night to our second station (Y1M5).

2011 - R/V Wecoma, 2011 Crew, Deployment, LDEO, SIO

Cruise Summary

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Dr. Robert Dziak contributed this cruise summary:

“The OBS deployment cruise was an unqualified success. Our
highly efficient team of sea going professionals was able to maintain a
brisk deployment schedule and completed all 25 ocean bottom seismometer
deployments within 8 days. We averaged 3 deployments a day, including
time for instrument surveys to derive their precise locations. The only
thing that suffered was our sleeping habits, but it was well worth it!
We also wish to express our gratitude to the Captain, crew, and Marine
Tech of the Wecoma for their hard work that allowed our project to be
successful”

“All 25 SIO and LDEO instruments were deployed with sites prioritized
prior to the cruise in consultation with the community to focus on
different scientific questions.  This prioritized sequence was further
modified prior to the cruise to accommodate recommendations from the
Oregon Fishermen’s Cable Committee (OFCC), The Oregon Trawlers
Association, the Quilete and Quinault tribes, and the Canadian Trawlers
Association, all of which represents the various fishing communities on
the Oregon, Washington and Canadian continental margins.  Of the 25
instruments deployed, one SIO Abalone  instrument lost its anchor as it
was being deployed. Another Abalone was deployed in its place as a spare
anchor was sent to Newport during the cruise. We returned to port
briefly after deploying the first 24 instruments, and returned to the
site to deploy the lone remaining Abalone.  All instruments will remain
on the seafloor until the summer of 2012.”

2011 - R/V Wecoma, 2011 Crew, Missions

Last Day at Sea

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We deployed the 24th seismometer at 9: this morning. The atmospheric pressure is dropping and the seas are rising, making the deployments more challenging. The roll of the ship increases the difficulty of both getting the seismometer to the rail and successfully releasing it over the side. We are heading back to Newport to pick up another anchor plate for one that we lost a couple of days ago. We’ll be doing a “touch and go”, without even putting out the gangplank. Fortunately, the last site is close to Newport.

At 9:50, seven of us met in the wheelhouse for a live Skype broadcast to HMSC. Tracy Crews organized “Career Day” for high school students and we responded via two way video to student questions from the Hennings Auditorium. Our virtual presence was projected on its large screen.

Bob Dziak – Chief Scientist – Professor, Marine Geophysics, OSU,  – What are you studying out there? What’s it like working at sea?

Dave Ogorman – Marine Instrumentation Engineer, Wecoma – How did you choose this career?

David Gassier – Ocean Research Engineer, Lamont-Doherty Earth Observatory, Columbia University – What is your background? Is there a specialized degree in Ocean Engineering?

Del Bohenstiehl – Co-chief Scientist – Associate Professor – North Carolina State University – What do you like most about being a scientist?

Matt Fowler – Mooring and Instrumentation Engineer – Research Assistant, OSU – What is your background? What do you enjoy most about your job?

Martin Rapa – Development Engineer, Scripps Institute of Oceanography – What did you have to consider when designing an underwater seismometer?

 

Tag lines are used to stablize the deployment

 

Matt is struggling with a jammed quick release mechanism
2011 - R/V Wecoma, Deployment, Missions, Seismometers

Off the coast of Washington

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Wednesday afternoon, October 19th – Off the coast of Washington at the edge of the continental margin

We just deployed another Cascadia seismometer. It will take 65 minutes to reach the ocean floor, 2630 meters below. It will take another hour to conduct the acoustic survey, as the Wecoma cruises in a kilometer and ½ circle overhead.

Ready to be released

 

Wecoma’s crane is lifting the seismometer over the side

 

It takes at least 5 crew members to deploy a seismometer
2011 - R/V Wecoma, Deployment, Seismometers

Wednesday’s Sunrise

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The weather has deteriorated somewhat, but is still serviceable.  We deployed two seismometer last night and another one this morning. Since we are in deeper water, it takes longer for the seismometer to reach the bottom.  A acoustic survey is immediately conducted to determine its exact location in three dimensions; latitude, longitude and depth. The Wecoma circles the seismometer location as the acoustic release sends signals to the ship.

Wednesday’s Sunrise
2011 - R/V Wecoma, Deployment, LDEO, Seismometers, SIO

A Beautiful Monday at Sea

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We have traveled north to test two Cascadia seismometers that were deployed earlier during the first leg during July. A specific frequency of sound (between 9 and 13 kilohertz) is sent down to check if the instrument package is working. Sometimes a fishing trawl can flip over the seismometer, rending it useless. If the instrument is working, it responds with a series of audio chirps that are picked up here on the Wecoma.

So far we have deployed five Cascadia and four Abalone seismometers. Another five are scheduled for deployment through the night.