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Thursday 2 October 2014

UCD scientists find volcanic seabed off Donegal coast that could cause Irish tsunami

Greg Harkin

Published 08/08/2014 | 02:30

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The scientific breakthrough came on the Rockall Bank, a marine bed the size of Ireland which lies more than 500kms out to sea.
The scientific breakthrough came on the Rockall Bank, a marine bed the size of Ireland which lies more than 500kms out to sea.

A team of scientists has found a previously undiscovered volcanic seabed fault off our west coast which could one day cause a tsunami.

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The scientific breakthrough came on the Rockall Bank, a marine bed the size of Ireland which lies more than 500kms out to sea.

Thirteen scientists, led by UCD's School of Geological Sciences, used a remotely operated vehicle at depths of up to one kilometre to find a new slope facing the west coast which could affect Ireland if it were to fracture again.

Among their discoveries was an abundance of a rare protected fish called the Orange Roughy, which can live for up to 150 years.

But it's the discovery of the volcanic structure - or fault - which has stunned the scientific team aboard the Marine Institute's RV Celtic Explorer.

"The faulting or fracturing of the earth's surface under the sea is not as rare as people might think, but because it is not visible it is often not considered," said Dr Aggeliki Georgiopoulou from UCD.

"The research of the scarps in this area will provide us with key information on the possibility of future land-slides in this region. As this particular slope is facing Ireland, if there were a new landslide to occur, we need to estimate if it would impact the Irish west coast."

The scientists representing eight nationalities and led by Dr Aggeliki Georgiopoulou and Dr Veerle Huvenne from the National Oceanography Centre in the UK spent two weeks using a remotely-operated vehicle to study the Rockall Bank's ocean floor.

They will now review 50 hours of seabed footage to see if a new landslide 520kms away could cause a tsunami.

The deep-sea escarpments they found were formed around 15,000 years ago.

"During the expedition we discovered that the scarps in this area are actually very different from one another both geologically and biologically, which we hadn't anticipated as they are in such close proximity to one another," said Dr Georgiopoulou.

With 50 rock samples and over 20 gravity cores retrieved, the team hopes to be able to explain this diversity.

Landslide

"We now need to further review the samples and data to help answer questions such as: do these differences in the terrain mean that this wasn't one single landslide? Could these escarpments have formed in different episodes and that's why they look so different?" said the UCD scientist.

"This is the first time we took such a close look at a submarine landslide so it will take us some time to analyse the video - this is completely new information for us. The video footage has also revealed that sea-floor pinnacles evident on the Irish National Seabed Survey map are in fact volcanic edifices, so far not documented or included in the geological maps of the Irish offshore," she said.

The group say their research may help them to understand the geologic behaviour of sediments and rock on slopes under the sea and establish a better understanding of the stability of our continental slope.

"The use of the new gravity corer provided scientists with an opportunity to retrieve three metre core sediments from areas under the seabed that haven't been reached before," said Dr Veerle Huvenne.

"Also capturing footage and taking samples using the Holland I gave us an unprecedented look at the terrain. It was as if we were in the field itself, walking around and selecting exactly the samples we needed, instead of taking a blind hit in 1000m water depth.

"Now we know exactly where each of our rock samples, short cores and biological samples came from," she said.

Both scientists said the research was also about protecting marine life in the event of mineral exploration.

It may also lead to the discovery of new medicines.

Irish Independent

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