Monday, March 26, 2012

A message from the South Atlantic

Hello readers, this is Will and I am almost exactly half a world away from Langseth. You may have seen in other blogs that I am one of the PIs on the Shatsky seismic project, was there for the previous cruise of Langeth in 2010, and was supposed to be there this time. Unfortunately, ship scheduling did not permit it because I ended up with two cruises scheduled for the same time. I am currently on the R/V Melville in the south Atlantic Ocean where we have just wrapped up our work investigating the Walvis Ridge seamounts. I am at 35°S and 1°W, almost exactly at the spot half-way around the world from Shatsky Rise. Although we have just finished our work, it will take Melville about 4 days to get back to land because we are in the middle of the ocean. By that time, Langseth should be shooting seismic lines.

I had hoped to be onboard Langseth for this cruise, which is an extra cruise for our project because the last one had much bad luck and could not finish our seismic lines, even with 60 days at sea. For a while, it looked like I might have 24 hours to get from Cape Town to Yokohama (the original starting place for the Langseth cruise), but ship schedules shifted and the two cruises overlapped. There are many considerations in setting up ship schedules and PI schedules is only one of them. After 49 days at sea on the Melville, I’m not sure how useful I would be to my colleagues on Langseth because I have been working all that time without a break and I am very tired and my brain is about fried. When you are a PI on a cruise, you typically work 12 hours a day. Ship operations may not take your complete attention, so I am often working on writing a paper or a chapter for my textbook, but you need to be there and watching all the time so that if something goes wrong or a decision has to be made, you are on top of it. So for the last 45 days, I get up in the morning and have coffee, go workout, spend 12 hours or more in the lab, go to bed, and repeat. My biggest source of entertainment is to read a paperback novel for a little while before I fall asleep. Oceanographic cruises are very demanding, but there is no other way to get the data that we seek so far from land.

Getting time on the Langseth is huge for a marine geophysicist. We spend years writing grant proposals in hopes that we will be one of the lucky ones to get a cruise (which we hope to be able to go on). The Langseth is our “telescope” for seeing deep into the Earth to help unravel its secrets. Previous cruises to Shatsky Rise had only small-source, single channel seismic profiling equipment, so they could only see through the sediments to the top of the igneous rock (we often call it “basement”). With Langseth’s large airgun array and multichannel streamer, we have a system that can bounce sound waves off horizons that are many kilometers deep – and this can tell us about the structure of the Shatsky Rise volcanoes, which helps us to figure out how they formed. I will be following Jun and my students and hoping that the cruise will be successful. I know that they are in good hands with the Langseth seismic techs who are really good at what they do.

(posted on behalf of Will Sager)

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