We left off last time with a tour of our sleeping quarters thus it seems only appropriate to now walk through the room where we spend most of waking hours; the main science lab. Located one level below the gun deck, the main lab operates 24 hours a day controlling every aspect of data acquisition from monitoring the multichannel streamers and air-gun arrays to building the computers needed to process the terabytes of data that barrel in.
It can safely be said that when acquiring 3D seismic data during which approximately 6.5 terabytes of raw data will be recorded over 43 days you can never have enough computers. In the main lab, laptops and computers occupy every surface. Stand-alone computer monitors duck taped onto desks sit next to laptops anchored by bungee cables. Power cords, Ethernet cables, and USB connections snake across tables in every direction periodically diving down into a dark power outlet. A bank of computer screens approximately 12 monitors wide and 3 monitors tall encircles nearly half of the lab. These screens (39 in total) act as terminals that allow us to monitor and control a myriad of processes that are summarized in the image below. Possibly of greatest importance are the terminals dedicated to “driving the ship.” We aim to always have the four streamers following in perfect straight lines behind the ship however, cross-currents make this is a difficult charge. Given the length of 6 km (3.7 miles!) and the weight of the streamers, it is akin to a toy boat towing four 23 m (75 ft) fishing lines straight behind it on a windy day. Thus to keep the streamers in the optimum orientation with respect to our acquisition line we continuously nudge the ship north and south while pulling the heads of the streamers with us. All of the steering is done from a combination of three monitors with the use of the software package “Spectra,” which in the simplest sense determines real time data coverage given the location of the air guns and the streamers.
Of equal importance are monitors that display the health of the four streamers and the two air-gun arrays. We aim to keep the streamers at a constant depth relative to the air-gun arrays and also at a depth that keeps them protected from passing ship traffic. In this part of the Atlantic fishing vessels are common and with our gear sitting kilometers behind our ship and 12 m (40 ft) beneath the sea surface one could see how a vessel might not know that it is there. Therefore, whenever we see an approaching boat we implore them to keep a safe distance away both for the safety of their vessel and for our gear.
Additionally, we use this bank of terminals to monitor for the presence of critters in the water, the weather and sea conditions, and the health of the EM122 multi-beam. Sitting back from the semi-circle of computers is another set of desks where the we, the students and scientists, stake our claim. Outfitted with no-slip fabric and duck tape, we have covered the back of the room with our computers, which we use for pre-processing and quality control (QC) of the incoming data.
That about covers the main lab, they keep it pretty cold down here for the sake of the computers so I’m headed up to grab another sweatshirt before I get frost bite. Stay warm out there!