Ireland isn’t known as a tsunami hotspot, but the risk isn’t zero

3 Apr 2019

Prof Frédéric Dias, MaREI and the UCD School of Mathematics and Statistics. Image: Vincent Hoban/UCD

MaREI’s Prof Frédéric Dias is using maths to help us better understand enormous waves that could hit Ireland one day.

In 2009, Prof Frédéric Dias joined University College Dublin (UCD) to work on wave energy converters and is now leading the wave group at the Centre for Marine and Renewable Energy (MaREI) at the university.

Elected as a member of the Royal Irish Academy in 2016 and the Academy of Europe in 2017, Dias recently received his second Advanced Grant from the European Research Council, worth €2.5m.

What inspired you to become a researcher?

Funnily enough, it was not by inspiration. At the time, I had to do my French military service and I found out that I could replace it with a ‘civil’ service and one possibility was to do a PhD in the US. This is the reason why I started a PhD! And I liked it, so I decided to continue my career as a researcher.

Can you tell us about the research you’re currently working on?

I am working in the general field of water waves. Presently I am working on four main projects:

1: Understanding extreme nearshore wave events through studies of coastal boulder transport

This project describes mechanisms by which hydraulic fracture creates boulders from cliffs, bedrock platforms, and how these boulders can be transported by waves. Laboratory experiments have shown that traditional approaches cannot explain which waves can transport boulders and how.

This project is in collaboration with Williams College (Prof Rónadh Cox) and Queen’s University Belfast (Prof Trevor Whittaker) with a focus on the Aran Islands. How the project started is interesting. One day, I received an email from Cox who had read one of my papers in the Journal of Fluid Mechanics. This paper showed that run-up amplification can occur under some circumstances. I replied, and soon after we decided to apply for funding through the US-Ireland scheme of Science Foundation Ireland. In a sense, this project was quite unexpected but turned out to be very productive.

2: Development of an operational tool for predicting tsunami inundation and induced currents

Tsunamis are highly destructive, long-duration disasters that in most cases allow for only minutes of warning before impact. Even though there have been significant advancements in warning methodology, pre-disaster preparedness and basic understanding of related phenomena, the vulnerability of port and maritime assets to tsunamis remains poorly understood.

The most recent tsunami in the history of Ireland was the 1755 Lisbon tsunami, which generated two-metre waves in Kinsale. A similar tsunami nowadays would cause much damage because of the larger number of boats and also pose a danger to human life.

The aim of this project is to survey the available numerical tools, and then to investigate which models can be improved using a variety of approaches.

3: Coupled wave ocean models

The sea state is an essential climate variable by itself, and is defined by the random succession of waves, which is generally very well described by the directional wave spectrum.

The knowledge of coastal oceanography is still limited. We are studying the two-way coupling between waves and currents, and the impact of submerged structures on wave and current fields. We developed a general numerical model capable of simulating wave current interactions, and this will be applied to a specific site on the west coast of Ireland, namely Galway Bay.

4: Wave energy resource of the north-east Atlantic Ocean

We are improving our knowledge of the wave energy resource in the north-east Atlantic by answering the following questions:

  • How will the wave energy potential change in the future due to climate change?
  • What will the consequences of this change be regarding the deployment and production of wave energy converters?
  • How well can the wave energy potential be inferred from the atmospheric conditions?

We have shown that we can expect a decrease of up to 20pc in the wave energy potential in certain parts of our area during winter by the end of the 21st century. But even with this decrease, the north-east Atlantic remains a highly energetic area. By the end of the century, we can also expect a southerly shift in the mean wave direction off the west of Ireland in winter.

The highly energetic and potentially dangerous wave states occur often in the Irish nearshore, with up to 16 metres in wave height seen in the winter of 2013-2014, according to our simulations. The information on these events can be used to possibly determine the ways to decrease their devastating impact on the wave energy converters, and to determine deployment locations which are the least affected.

In your opinion, why is your research important?

There is a huge potential in marine renewable energies (MREs). The past difficulties must not stop us from continuing the development of MREs.

Even though Ireland isn’t the first country one thinks of when talking about tsunamis, the risk isn’t zero. Moreover, people travel more and more, and the probability of encountering a tsunami is also increasing.

Our knowledge of what happens in the water column is still incomplete. Understanding currents is important for several issues – such as sea pollution – and the impact of big storms is poorly known. Inundation and erosion are also important issues.

What are some of the biggest challenges you face as a researcher in your field?

There is short-term vision of research as MREs require at least 15 years to be profitable. Another challenge is that there is too much research which is duplicated. Researchers tend to work in isolation, whereas true collaborations remain a challenge.

Another challenge is climate change. It is our duty to talk about climate change and to take part in public discussions on climate change. However, it is extremely challenging, simply because we don’t know the answers to all the questions and we are constantly challenged.

Are there any common misconceptions about this area of research?

One misconception is that one tends to forget that water waves are an extremely difficult topic, which requires years to understand the fundamentals.

Are you a researcher with an interesting project to share? Let us know by emailing with the subject line ‘Science Uncovered’.