What threat do turbidity currents and submarine landslides pose to strategic submarine telecommunications cable infrastructure?

Lead Research Organisation: National Oceanography Centre
Department Name: Science and Technology

Abstract

It is not widely known that the global economy relies on uninterrupted usage of a network of telecommunication cables on the seafloor. Yet these submarine cables carry ~99% of all inter-continental digital data traffic worldwide, as they have far greater bandwidth than satellites. Over 9 million SWIFT banks transfers alone were made using these cables in 2004, totally $7.4 trillion of transactions per day between 208 countries. Our dependence on these cables is growing, for example there were 15 million SWIFT bank transactions last year. Submarine cables thus have considerable strategic importance to the UK because this data traffic includes the internet, defence information, financial markets and other services that underpin daily lives. This project is timely because submarine cable breaks are a notable omission from the UK National Risk Register. It focusses on the industry challenge of why exactly, how often, and where are seafloor cables broken by natural causes, primarily subsea landslides and sediment flows (turbidity currents). These slides and flows can be very destructive. A flow in 1929 travelled at 19 ms-1 and broke 11 cables in the NE Atlantic, running out for ~800 km to the deep sea. A repeat event would break far more cables today. It is difficult to mitigate against multiple breaks from such flows/slides because data traffic cannot be re-routed along adjacent cables. This contrasts with trawling (or other human activities) that break a single cable. This study is in conjunction with Global Marine and the International Cable Protection Committee. The ICPC is the global umbrella body for the submarine cable sector, and hosts Talling's Royal Society Industry Fellowship. This will be the first study to statistically analyse a global database of cable breaks and causes. It will use novel field and laboratory experiments to show how cables abrade or break.
The main project impacts are: (1) We will provide our industry partners (ICPC, individual cable companies) with the first global statistical analysis of the frequency and causes (earthquake, typhoons) of cable breaks. (2) We will map geographic "pinch points" in the global seafloor network that are most at risk from specific hazards; thus helping our partners to design cable routes. These results will help to assess where future climate change is most likely to impact upon cable routes. (3) Laboratory experiments and a novel full-scale field experiment will help our industry partners to understand exactly how cables are broken by submarine flows (and why they sometimes fail to break). Results will be presented at workshops with individual cable companies, and at the ICPC's plenary meeting. Such meetings will provide a global forum for discussion of future strategies for reducing cable breaks. (4) A briefing document will be delivered to the UK Natural Hazards Partnership and Cabinet Office that sets out the basis for whether submarine cable breaks should be included in the UK National Risk Register.

This project has wide relevance for multiple geographic and geologic settings and the global subsea communications industry. Other type of expensive and strategically important seafloor infrastructure are also susceptible to impacts by submarine flows/slides, including export pipelines and in-field flowline for oil and gas, and umbilicals that transfer chemicals, power and communications. This project's findings will help to assess the risk posed to these other types of subsea infrastructure by submarine flows/slides. Our project partners include those interested in risks to seafloor pipeline used to carry treated water (Carroll at ScottishWater), and oil and gas networks worldwide (Jobe, Sylvester, Armitage). Submarine flows deposit layers of sand that now form many valuable oil and gas reservoirs. We will also communicate insights from our project into these processes to interested partners (e.g. Jobe at Shell, Sylvester at Chevron, Armitage at ConocoPhilips).

Planned Impact

The main project impacts are: (1) We will provide our industry partners (ICPC, individual cable companies) with the first global statistical analysis of the frequency and causes (earthquake, typhoons) of cable breaks. (2) We will map geographic "pinch points" in the global seafloor network that are most at risk from specific hazards; thus helping our partners to design cable routes. These results will help to assess where future climate change is most likely to impact upon cable routes. (3) Laboratory experiments and a novel full-scale field experiment will help our industry partners to understand exactly how cables are broken by submarine flows (and why they sometimes fail to break). Results will be presented at workshops with individual cable companies, and at the ICPC's plenary meeting. Such meetings will provide a global forum for discussion of future strategies for reducing cable breaks. (4) A briefing document will be delivered to the UK Natural Hazards Partnership and Cabinet Office that sets out the basis for whether submarine cable breaks should be included in the UK National Risk Register.

Hart (Atkins), Searle (Cathie Associates), Nichols (Flintshire Geophysics) are senior industry consultants advising on placement and routing of subsea structures, including cables. Whitehouse's (HR Wallingford) extensive experience in physical flow-structure interaction will be particularly relevant during experiment design. Will Carroll (ScottishWater) is responsible for resilience of seafloor pipelines. Existing collaborators from major oil and gas operators have also pledged support, including Jobe (Shell), Sylvester (Chevron), and Armitage (ConocoPhilips). This diverse combination of partners will ensure that the project's relevance to the cable industry, but also allows for broader translation of findings to other vulnerable seafloor infrastructure. Key outcomes will be improving partners' understanding of risk on a global and local scale, via briefing meetings and wider dissemination by presentations at key industry meetings (e.g. SubOptic, ICPC plenary).

An initial measure of our project's impact will be the depth and breadth of industry representation at key meetings (e.g. ICPC and SubOptic meetings) and individual project workshops. A second measure will be feedback from the ICPC on our summary report that combines (i) statistical analysis of cable breaks and their causes, (ii) maps of pinch points for different hazards, and (iii) insights into how exactly cable are broken (or remain unbroken). Submission of our project's report to the UK Natural Hazards Partnership and UK National Risk Register will be a final key outcome from the project.

Publications

10 25 50

 
Description The global economy relies on uninterrupted usage of a seafloor network of telecommunication cables that carry ~99% of all inter-continental digital data traffic. Submarine cables have considerable importance because this data traffic includes the internet, defence information, financial markets and other services that underpin daily lives. With trillions traded daily via subsea networks, multiple cable breaks in important regional hubs can have major implications. Repairs can cost up to £100 million. This project focussed on the industry challenge of why exactly, how often, and where are seafloor cables broken by natural causes, primarily subsea landslides and sediment flows (turbidity currents).

Global Marine Systems Ltd provided access to an industry database, which enabled the first global statistical analysis of the frequency and causes of cable breaks. Geographic "pinch points" at risk from specific hazards were identified; thus helping the partners, including the global umbrella body for the subsea cable community, to design more effective routes. A briefing document was provided to the Cabinet Office setting out the basis for why submarine cable breaks should be included in the UK National Risk Register. The project has enabled offshore industries and government to perform more informed risk assessments on a global basis.
Exploitation Route With trillions traded daily via subsea networks, multiple cable breaks in important regional hubs can have major implications. Repairs for telecommunication cables can cost up to £100 million. Avoiding areas of potentially hazardous seafloor can result in unfeasibly long pipelines; the cost per km can exceed £2M. Thus, identifying regions that are most prone to damage is important. Historically, industry hazard assessments for earthquake-triggered breaks were based on global maps of earthquake activity; however, the project identified that unless a region is fed by high volumes of sediment (e.g. by large rivers) then even large magnitude earthquakes may not necessarily trigger damaging flows. High seismicity areas do not therefore always need to be avoided, which opens up new opportunities for infrastructure; such as enabling shorter routes (potentially saving £Ms), or making previously unviable projects feasible. Findings were disseminated at major industry conferences (Offshore Technology Conference & ICPC plenary). Final reports were published as three peer-reviewed articles, co-authored by the ICPC Scientific Advisor (Carter).

The over-arching project aim was to gain and disseminate to industry and government a greater understanding of hazards posed by submarine slides and flows to seafloor cables. In order to raise awareness of the underappreciated threat posed to the UK, a briefing document was delivered to the UK Natural Hazards Partnership and Cabinet Office setting out the basis for whether submarine cable breaks should be included in the UK National Risk Register. Industry partners attended a workshop on "Hazards for Marine Infrastructure" at NOC Southampton. The response to the workshop was extremely positive; 15 representatives from 10 different companies attended. As a result of this project, offshore telecommunication and hydrocarbon industries can make more informed routing assessments, and design more effective repair strategies for areas prone to damage.
Sectors Digital/Communication/Information Technologies (including Software),Energy,Government, Democracy and Justice,Security and Diplomacy

 
Description This project is novel because it provided the first ever global view on subsea cable breaks by natural hazards for industry. Global Marine Systems Ltd provided unprecedented access to their global cable breaks database and guidance on its interrogation. This enabled the determination of specific triggering mechanisms for damaging sediment flows in multiple geographic and geologic settings for the first time. Thus, the project had unusually wide relevance for the global subsea communications industry and offshore oil and gas production activities. Feedback was sought from project partners throughout, including at the International Cable Protection Committee (ICPC) plenary meeting in Hamburg, via company visits in Houston, and to Carter in New Zealand. Partners were invited to a knowledge translation workshop, with presentations from both industry and academics. The first stage of the project involved analysis of the global database of cable breaks to understand what controls the frequency of cable breaks in different settings. To explore potential earthquake-triggered breaks, global earthquake databases were interrogated for moment magnitude, distance of epicentre, and intensity local ground motion at the cable break location. A valuable finding was that large magnitude earthquakes do not always trigger damaging sediment flows. The volume of sediment supplied to the continental slope is a stronger control on when and where damaging flows occur. The second stage explored how meteorological events such as tropical cyclones lead to cable breaks. Analysis of storm track and weather forecast data identified that cable breaks are not always broken at the peak of a tropical cyclone, but instead are often damaged several days after its passage due to the delayed response of river discharge. The influence of global warming appears to increase the likelihood of cable breaks offshore Taiwan (an important trading hub) due to the increasing passage duration of cyclones over the region.
First Year Of Impact 2016
Sector Digital/Communication/Information Technologies (including Software),Energy,Environment,Financial Services, and Management Consultancy,Government, Democracy and Justice
Impact Types Societal,Economic,Policy & public services

 
Description Evidence to Government Review of Threats to Seafloor Cables
Geographic Reach Multiple continents/international 
Policy Influence Type Gave evidence to a government review
Impact I gave written evidence to the Department for Digital, Culture, Media and Sport a review by their Telecoms Security Team on seafloor cables that carry > 95% of global data traffic. This aimed to understand what a significant loss of transAtlantic cables would have on the UK, and the implications for the national security risk assessment
 
Description Developing a Global Listening Network for Turbidity Currents and Seafloor Processes
Amount £846,000 (GBP)
Funding ID NE/S009965/1 
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 04/2019 
End 03/2024
 
Description How do deep-ocean turbidity currents behave that form the largest sediment accumulations on Earth?
Amount £509,950 (GBP)
Funding ID NE/R001952/1 
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 04/2019 
End 03/2023