Oceans are important in climate control and disaster staging, butthey  are hard to watch because of their vastness. Submarine telecommunication cables, previously used for data transmission, offer a way to improve seismic event early warning and climate monitoring through real-time data. The IOC is in charge of coordinating the United Nations Decade of Ocean Science for Sustainable Development 2021-2030, the “Ocean Decade”. This paper aims to explain how environmental sensors can be incorporated into undersea cables to improve the early warning system for seismic events and support long-term climate studies. It investigates the possibility of loading these cables with temperature, pressure, and seismic sensors to obtain cost- effective and continuous ocean observations. It also reviews legal, regulatory, and economic barriers and the part that ITU, WMO, and UNESCO/IOC can play in coordinating international efforts. This paper aims at a case study on the 2004 Indian Ocean tsunami and the 2025 Santorini earthquake to reveal the possible value of sensor-imbedded submarine cables for risk mitigation and disaster preparedness. The results of the study also show that there is a need for international cooperation, policy changes, and sustainable investment plans to leverage the potential of submarine cables for environmental sensing. Finally, the study identifies how scientific submarine cables can be incorporated into global early warning systems, with emphasis on their application to life and economic risk from climate hazards. Thus, the present study is significant from a practical standpoint and can be useful for designing further methods of applying submarine cables for environmental sensing purposes, as well as for enhancing international cooperation in this area. The conclusion contains the main recommendations for the implementation of the project, as well as the further directions of its development.

Introduction

Oceans are the earth’s source of climate control and are the first to show signs of natural disasters such as earthquakes and tsunamis. Oceans store more than 90% of the heat and 50 times as much carbon as the atmosphere in the Earth’s climate system.1 Long-time series data requires a very stable and reliable platform. Such a platform exists in the deep ocean: the subsea fibre optic cable systems that join continents and form the fabric of the Internet. However, the monitoring of deep-sea environmental changes and the detection of seismic activity in the underwater region is still a major challenge because of the large coverage area of the ocean. Submarine telecommunication cables that were originally built for data communication across the globe are now found to be suitable for monitoring the oceans. This paper discusses how environmental sensors can be fused into these undersea cables to form a real-time monitoring network that can monitor climate changes, detect seismic activities and provide early disaster alerts.2 The paper explores the potential of submarine cables in early warning detection systems and long-term climate change studies. Installation of temperature, pressure and seismic sensors into the submarine cable infrastructure would provide a cheap and sustainable way of oceanic observation. Also, the paper reviews the legal challenges faced by operators and the roles of International organizations in easing the process. This paper aims to determine the potential, challenges and future3 of submarine cables as a dual-purpose tool for environmental monitoring and disaster risk reduction from both the scientific and engineering perspective [4]. Finally, this paper aims to suggest few recommendations needed in this emerging sector for better environmental studies and global good.4 The key research questions addressed in this paper are: How can submarine cables improve disaster risk management and mitigation? What are the roles and responsibilities of International organizations (ITU, WMO, UNESCO/IOC) in adopting the submarine cable framework? What are the regulatory issues faced by the submarine cable operators and the coastal countries? What are the primary scientific parameters for climate monitoring and ocean observation5 using submarine cables? What is the economic viability of this project and the socio-economic benefits rendered by its implementation?

Review of Literature

Several studies have explored various aspects of submarine cables and their applications. For instance,⁷ investigated the strategic placement of SMART subsea cables for maximum impact but identified a gap in their integration with existing monitoring networks. Similarly,8 discussed international cooperation and standardization efforts led by organizations like the UN and ITU but did not address the legal and policy barriers to implementation9 examined the role of a global network of submarine cables in supporting ocean monitoring. Meanwhile,10 provided an overview of India’s protection. Lastly,11 proposed structured approach for engaging telecom companies and policymakers to integrate environmental monitoring into submarine cables but did not incorporate a cost-benefit analysis for equipping them with environmental sensors.

Research Methodology

The methodology adopted while writing this paper involved: 

-2 case studies, one was an old catastrophe and the other was a very recent calamity, emphasizing the impact of large- scale disasters caused by undersea earthquakes and tsunamis throughout history.

a) 2004 Indian Ocean Earthquake and Tsunami

b) 2025 Santorini earthquake

On December 26, 2004, a massive undersea earthquake with a magnitude of 9.1 struck off the western coast of northern Sumatra, Indonesia. This seismic event triggered a series of colossal tsunamis that inundated coastal areas across 14 countries, including Indonesia, Sri Lanka, India, and Thailand. The disaster resulted in over 220,000 fatalities and displaced approximately 1.7 million people. The total estimated economic loss is around $10-15 billion. Several submarine fiber-optic cables were damaged, causing internet and telecom blackouts. Millions of dollars were spent on emergency repairs. The widespread devastation highlighted the critical need for effective early warning systems and international collaboration in disaster response.12 Santorini, a volcanic island in Greece, has experienced multiple earthquakes throughout history, primarily due to its location in the Hellenic Arc subduction zone, where the African Plate is subducting beneath the Eurasian Plate. In early February 2025, the Greek island of Santorini experienced a significant seismic event characterized by an extensive series of undersea earthquakes. Over ten days, more than 12,800 tremors were recorded. As of February 6, over 11,000 individuals had evacuated Santorini. These recent tremors again highlighted the importance of early warning detection systems in place for improved evacuation plans.

It is observed that the deep ocean temperature is steadily rising at a rate of 50m0C/decade and sea level rising at 5 mm/yr. The thermal expansion of water also accounts for 50% of the water level rise in the sea. These enhanced cables can measure ocean temperature changes at different depths, helping scientists track long-term warming trends. It provides continuous real-time data, unlike traditional ship-based or buoy-based observations that are periodic. Pressure sensors on cables detect small variations in water column pressure, contributing to more accurate measurements of sea level rise. Cables can measure ocean currents and salinity, critical for studying how heat and carbon are transported across the ocean thereby helping refine models on El Nin˜o and La Nin˜a phenomena, which impact global weather patterns.

Due to its volcanic and seismic activity, Santorini is vulnerable to underwater landslides and tsunamis. Continuous monitoring of seafloor activity and tectonic shifts would allow for better hazard mapping. Had a scientific submarine cable system been in place before the recent Santorini earthquake swarm, authorities might have been able to predict and monitor the event more accurately, reducing panic, optimizing evacuations, and improving long-term resilience. Investing in this technology could greatly enhance disaster response and preparedness for future seismic events in the region.13

The LOS convention does not classify dual-purpose telecom marine data cables as Marine Scientific Research (MSR). Coastal countries could impose significant restrictions and delays on the installation and maintenance of submarine cables and threaten the reliability of communication by such cables. Submarine cable operators must determine whether they have sufficient legal-regulating flexibility and a business case for such deployment. Coastal states claim to exercise rights over marine zones adjacent to their coastlines.

Existing earthquake and tsunami early warning systems rely on seismic stations, GPS networks, and ocean buoys, but they have gaps in coverage, slower data transmission, and limitations in detecting deep-sea events. These scientific submarine cables are integrated with various real-time monitoring highly precise sensors such as seismic sensors to detect vibrations and sound waves, pressure sensors to measure variations in seafloor pressure, which can indicate tsunamis, sea level rise, and ocean circulation changes, temperature sensors to provide high-resolution ocean temperature profiles, crucial for tracking global warming trends. The pH and carbon sensors to measure ocean acidification by detecting pH levels and CO2 concentrations and ocean current sensors to measure the velocity and direction of ocean currents, which affect heat transport and climate variability.

Roughly estimation of the cost (USD) has been developed and divided into 3 categories:

1. Fixed Cost: Cost incurred once to develop Green Repeater into final deliverable product. The point to note is that

each supplier will have its own fixed cost as each will modify its own repeater. This cost doesn’t include the demonstration cost but is most difficult to estimate. Development cost, which depends on the instruments requirement and the extent is a new development, and is estimated to be in the range of 15-20 million USD (including sea trial).

2. Unit Cost: Cost includes the cost of each repeater and the additional fibre that must be added to the cable. Additional fibre is required because of the difference in compatibility with that of the old repeater due to the change in complexity of the new repeater.

3. Operating Cost: After deployment, no direct cost is required for instruments so operating cost is assumed to be zero. The cost of collecting, storing and analyzing data is not considered.

Fig. 2. Maritime Zones and Legal Continental Shelf Delimitation

Recommendations

Engage with International legal bodies14, such as the International Telecommunication Union (ITU) and the International Cable Protection Committee (ICPC), to push for an updated interpretation of UNCLOS provisions to better reflect modern telecom and marine research needs. Prioritize deployment first in earthquake-affected and tsunami-stricken areas. Bilateral or Regional Agreements may be signed with Coastal States to boost this research. Form partnerships with coastal state entities to ensure local investment and involvement, potentially reducing regulatory barriers. Provide coastal states with detailed environmental impact assessments, economic benefits, and security measures to ease concerns and expedite approvals. By integrating legal, diplomatic, business, and technological strategies, submarine cable operators can better navigate regulatory hurdles and ensure the continued reliability of global communications.

A. Global Coordination and Policy Formulation

An international system led by the UN (e.g., under UNESCO-IOC, ITU, or WMO) should be established to har- monize rules and deployment regulations. The submarine cable project should be worked on by coastal countries, especially in seismically active and tsunami-prone areas. Establish global guidelines for real-time sharing of seismic and oceanographic data to reinforce early warning disaster systems.

B. Sustainable Funding and Investment Strategies

Support government-to-government, telco-to-government, and research institution-to-government collaboration to co- fund such smart submarine cable initiatives. Appeal to inter- national financial institutions (e.g., World Bank, IMF, Green Climate Fund) to provide funds to developing nations to install such cables. Encouraging private companies with tax incentives or subsidies to add these sensors to their submarine cables.

C. Overcoming Legal and Security Issues

Clarify ownership of the data through explicit agreements regarding who controls and owns the data acquired to avert conflicts between governments and telecommunications providers. Institute encryption and cybersecurity measures to ensure that data breaches or sabotage of the underwater cables are averted. Undertake environmental impact studies before installation to ensure that marine ecosystems are preserved.15,16

D. Public Awareness

Since the incorporation of sensors into the repeaters would take many years to come into actualization it would be advantageous to raise public awareness about the potential of submarine cables to speed up the process of manufacturing repeaters. Activities in progress and further course of action can be highlighted by ITU, WMO and UNESCO/IOC at press conferences and media.

E. Eco-Friendly Submarine Cable

It is important to link submarine cables with “GREEN” as it builds the trust of goodness among manufacturers, operators and other participants which in turn creates a positive impact as there is an increase in interest in going “green” among the general public. Also creating public relations is a bonanza for these types of telecom implementation as “green” will be highly beneficial.17

F. Engineering Workshops for Efficient integration

In order to make the process of integrating the sensors with repeaters efficient, a workshop can be arranged to bring sensor manufacturers and cable repeater manufacturers on a common platform. This will create a mutual understanding between both the participants. For diverse international participants, nominations from various science organizations can be requested by ITU, WMO and UNESCO/IOC.

Conclusion

Scientific sensors installed within next and future generations of submarine cable repeaters at the sea floor present an extraordinary opportunity and vision for ocean/climate monitoring and disaster risk reduction. Engaging the mutual interests and leadership of commercial telecommunication companies with the international scientific community through the support and advocacy of the United Nations – ITU, WMO, and UNESCO/IOC – builds upon the momentum generated for this vision.

Current earthquake and tsunami early warning systems are based on seismic stations, GPS networks, and ocean buoys but suffer from gaps in coverage, delayed data transmission, and limitations in the detection of deep-sea events.

Instead of the conventionally available early warning detection systems, these scientific monitoring submarine cables possess the following benefits:

a) Real-Time Deep-Ocean Monitoring: Direct real-time observation of deep-sea seismicity. This is important for the monitoring of underwater earthquakes, landslides, and volcanic eruptions that can produce tsunamis.

b) More Rapid and More Accurate Tsunami Warnings: Because they span thousands of kilometers of ocean floor, they can sense seafloor pressure changes much sooner than surface buoys. This enables more rapid tsunami warnings, giving valuable extra minutes for evacuation.18,19

c) Improved Coverage and Ongoing Data Collection: Such cables already form part of an ocean-crossing global telecommunications network and enable extensive and ongoing data collection in areas that were previously unmonitored.

d) Economically Efficient and Scalable Dual-Use Infrastructure: Incorporating sensors into submarine telecommuni- cations cables, systems enable cost-efficient, scalable, and multi-purpose monitoring for scientific and commercial use. 20,21

The effective global deployment of these scientific submarine cables depends on intense international cooperation, financing arrangements, and technology innovation. By incorporating the proposed recommendations, these cables may emerge as an essential world infrastructure for climate observation, disaster mitigation, and oceanic research, thereby saving lives and securing economies against natural disasters.

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