A recent study highlights how these powerful underwater events can sever cables, leading to widespread internet disruptions and costly repairs.
Underwater avalanches, or turbidity currents, pose a significant threat to the global undersea internet network, which spans over 1.5 million kilometres of submarine fibre optic cables, according to a new study. These avalanches occur when sediments on the ocean floor are suddenly displaced, creating powerful, fast-moving flows. As these currents travel across the seabed, they can sever or damage the delicate cables that transmit internet and communication data across continents. Disruptions caused by these events can lead to significant global internet outages, highlighting the vulnerability of the world’s digital infrastructure to natural underwater phenomena.
Christopher Stevenson, the lead author of the study and Senior Lecturer in Quantitative Sedimentology at the University of Liverpool, writes, “My new study of an ancient underwater avalanche challenges our understanding of how underwater avalanches develop and may change the way geologists assess their risk potential.”
According to ScienceAlert, it is estimated that there are now over 550 active seafloor cables around the world with a combined length of 1.4 million km—enough to wrap around the circumference of the Earth 35 times. When an underwater avalanche breaks seafloor cables, the effects can be widespread and expensive.
The 2006 Pingtung earthquake in Taiwan triggered underwater avalanches that cut many seafloor cables connecting southeast Asia with the rest of the world. The largest internet operator in China reported a 90% loss of traffic to the US at the peak of the event, and Taiwan experienced a 74%–100% loss in internet traffic to neighbouring islands. This damaged global markets by slashing the number of financial transactions that could happen. Repairing the network to full capacity took 39 days and millions of dollars in shipping time.