Half-way through


Our expedition is moving along steadily. We have now completed collecting both wide-angle and seismic reflection data for our first profile. The Langseth is cruising toward our second line of survey which is about two days away (13hrs from now). In the past few days, we have had some very exciting experience with seismic acquisition including an opportunity to see how a hydrophone streamer was deployed into the water, 15 km of it.  The streamer is a carrier of hydrophones which we use to record the sound wave signals generated by our airguns that were reflected back to us from the subsurface. We have a set of hydrophones place every 12.5 m along the streamer. As watchers on the earliest shift of the day we got to spend a field day on the streamer deck and joined in with the crew to learn about streamer deployment and all of the advanced technologies that come with it. Putting out a 15-km-long line of hydrophones into the ocean is no trivial job. We were tasked with assembling “birds” and mounting them onto the streamer as it was rolled out into the water. A bird is a device that provides us control over the depth at which the streamer is towed below the sea-surface.  The compass mounted inside each “bird” also helps constrain the orientation of the streamer at any time. We installed a bird onto the streamer at roughly every 260 m. Besides birds, they are other high-tech devices that are attached to the streamer e.g. acoustic pingers, GPS and more. It's amazing to see how much technology is incorporated into the deployment of streamers. 

Valeria and I are mounting a "bird"
onto the streamer and sending
them out to the water.
By mid-day on the 13th, we had the airgun arrays in the water and started shooting. What is nice about MCS (multi-channel seismic) data is that we can see them almost as soon as the streamer records them. We are currently processing the collected MSC data which already shows some interesting geological features (e.g. suspected failed oceanic rift). Another 13 hours and we will be at our second survey site. In the meantime, we continue to monitor as the data come in while enjoying other fun activities aboard including Bridge (card game), music lessons, and especially the ping-pong tournament… Yupe, earth scientists can have quite a lot of fun at work, even in the middle of the North Pacific.

Luan Nguyen
Rice

Valeria putting together one of the
birds 
Airguns being deployed into the water





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