OBS Recoveries with JASON!

­­Recovery of OBS stations continues aboard the R/V Sikuliaq.  Although we are now one week into the three week cruise, we still sometimes encounter surprises.  For example, yesterday we discovered that one of our TRMs had landed upside down on the seafloor during deployment.  This “flipped” position meant we needed to switch from our plan to pick it up directly with JASON to a more flexible recovery method.

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This was a disappointing sight when we reached our station

So – how do you get a 1400lbs package of metal and electronics from the seafloor to the surface when its handles are buried in the gooey pelagic mud beneath it?  With ingenuity and teamwork, of course! We used an “elevator” to lift the station to the surface.  The elevator consists of a long reel of rope attached to both a float and a heavy weight.  The elevator is lowered overboard from a position carefully calculated based on ocean currents, water depth, and the TRM location.  It sinks to the seafloor, and JASON seeks it out and carries it back to the TRM.  (I’m reminded a little of scenes from “WALL-E”!)

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JASON carries the “elevator” back to the overturned TRM.

JASON operators then carefully hook the weighted-end to the TRM, and release the float to shoot back to the surface.  The reel of rope unspools behind it, allowing us to recovered our upside-down station using a ship-board winch.  All of this would be challenging enough, but the seas also threw us very strong currents, low visibility, and schools of curious fish!

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Can you imagine threading a bolt from more than 200 meters away?

In between station recoveries, we are also getting our first peeks at the recovered data.  Even a quick perusal serves as a reminder of why this data is important.  There are some beautiful signals for major regional and global earthquakes.  And due the high seismicity rate along the Alaskan margin, you can randomly select any two hour window and find at least one local earthquake!

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The November 30, 2018 earthquake.

 

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Local events

Stay tuned to the blog to learn about life and science aboard the Sikuliaq, including some of the strange things we’re hauling up from the seafloor with our seismometers!

Aubreya Adams, Colgate University

 

 

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1 thought on “OBS Recoveries with JASON!

  1. So very interesting of the research of the ocean. Thanks for letting us peer in.

    Like

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