Geohazard Investigation within the Irish Sea utilizing Seismic and Seabed Mapping Methods (GIST) – Weblog 5

Geohazard Investigation within the Irish Sea utilizing Seismic and Seabed Mapping Methods (GIST) 


twenty fourth October – sixth November 2019

The GIST survey days are few, we’re coming in the direction of the top of our offshore adventures now. The climate has been principally variety since leaving Dublin for the second time. Nevertheless, forecasts for Tuesday might need us again into port before we anticipated, bringing an finish to the survey.  
My title is Megan Dolan, I’m a analysis grasp’s pupil inside iCRAG, based mostly in each the Civil Engineering and Earth and Ocean Sciences departments on the Nationwide College of Eire, Galway (NUIG). Not like lots of our crew on board, my analysis is land based mostly. I volunteered to be a part of this survey to assist my colleagues purchase the info they want for his or her respective initiatives, to study offshore surveying and to have enjoyable. This has been my first (and hopefully not my final) offshore survey and I’ve loved day by day of it.
 RV Celtic Voyager crew expertly retrieving the passive acoustic displays from their seabed 
 RV Celtic Voyager crew expertly retrieving the passive acoustic displays from their seabed 

We’ve now retrieved all three of Eoghan’s hydrophones and moorings. It was thrilling to observe the buoys and hydrophones be lifted again onto the ship seven days after deploying them. As we dismantled every hydrophone to entry the collected sound knowledge on the motherboard inside, I felt like I used to be a part of a bomb squad. We uploaded the info and to our dismay, we found that one thing had gone mistaken and that our hydrophones had stopped working sooner than deliberate. Though we didn’t get as a lot knowledge as we hoped, we nonetheless have some nice submarine sounds. Yesterday we listened to trawlers which had sailed previous the hydrophones once they have been underwater and recording. We additionally listened to the heartbeat sound of our personal seismic sparker instrument which we have been utilizing to picture the sub-seafloor construction some two kilometres distant from the hydrophone. Regardless of shortcomings, we’re all more than happy with the sound recordings obtained by the hydrophones and Eoghan has his work lower out for him now to course of this knowledge.

Sparker tools onboard the GIST survey

Sparker tools onboard the GIST survey

As a result of noise that our sparker instrument makes, we’re required to look out for marine mammals for a while earlier than the we start our seismic surveys. Eoghan is our Marine Mammal Observer (MMO) and he makes use of high-tech binoculars and stands on the bridge in search of mammals within the water. We don’t conduct a seismic survey if Eoghan spots any mammals on the market as a result of it’s nonetheless unknown if the sound of the seismic sparker may be detrimental to those animals. Nevertheless, probably the most superb factor occurred final evening. We have been visited, mid-seismic survey, by a pod of dolphins. Between fifteen and twenty dolphins swam with the ship for about forty minutes, leaping out of the water and swimming forwards and backwards beneath the ship to both aspect. It was a marvellous website and people of us who have been on shift, stood exterior in the dead of night watching the dolphins play. It might appear that the dolphins didn’t thoughts the noise of our sparker instrument within the slightest. 
We’ll proceed to make use of the time we have now left to resurvey the WW1 shipwrecks and conduct one other seismic survey. That’s all for now. Keep tuned for extra tales of the GIST survey.
You keep elegant, readers of the GIST weblog.
Weblog from NUIG and iCRAG masters pupil Megan Dolan.

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