The entire world depends on the ability to communicate through technology as a means of economic, social, and interpersonal survival. This modern-day necessity underscores the importance of maintaining a resilient telecommunications infrastructure. A recent study published in Science on September 7th, has unveiled a previously overlooked threat to global connectivity. Last year Tonga, an island country in Polynesia, was impacted when the underwater volcano Hunga Tonga–Hunga Ha’apai erupted. It was not merely a geological event; it was a wake-up call. Researchers found that this single underwater volcanic eruption destroyed nearly 124 miles of crucial subsea telecommunication cables.

Michael Clare, and a team of researchers from the National Oceanography Centre, analyzed observations of volcanic flows triggered during the 2022 Tonga eruption. Through meticulous analysis of cable breakages, bathymetric surveys, eruption observations, and rock core sampling, Clare and his team uncovered the true nature of this disaster. They found that the materials ejected from the eruption collapsed into the ocean, creating a fast and highly destructive underwater debris flow known as a “density current.” Traveling at 75 miles per hour, these density currents were faster than those triggered by earthquakes, floods, or storms. They broke over a hundred miles of seafloor cables, cutting off a nation from the rest of the world. Like many island nations, Tonga relies on just a single underwater cable, about the thickness of a garden hose to allow for internet and communication access. Repairing undersea cables is costly and time-consuming, and in the case of Tonga the international cable took five weeks to repair, and the domestic cable required 18 months for replacement.

This event was dubbed the most powerful eruption of the 21st century and highlights the vulnerability of the modern internet, especially for countries like Tonga that heavily depend on undersea cables. It is not just about these islands however, according to Google data, nearly 98 percent of global internet traffic is channeled through these undersea cables, which constitute approximately 436 cables spanning a vast distance of 1.3 million kilometers. Think of all that underwater data traversing the globe connecting people, commerce and countries.

This study emphasizes the need for vigilant monitoring of the Earth’s underwater ecosystem to safeguard these vital cables and prevent disastrous data blackouts. It also reminds us that it is best to ensure geodiversity of where one’s data is stored, and diversity in how we access data whether locally, nationally and most certainly globally.