Subsea Cables & Internet Infrastructure

A turbidity current is the likely culprit for the WACS trunk outage. The same holds true for the 2Africa Ivory Coast branch failure. The Taiwan earthquake of December 2006 is instructive in this regard. The 22 knocked out cables failed in sequence over the course of several hours. So the sheer force of the earthquake was not responsible. Instead, the seismic event caused sediment to begin moving down the undersea slope of Taiwan's continental shelf. This was not a gentle slope, but rather the steep sides of the Kaoping subsea canyon, which is 4 kilometers deep. As the chart shows, cables went dark in sequence radiating from the epicenter outward as this undersea tidal wave traveled down the sides of the subsea canyon. The turbidity current traveled at speeds ranging from 3.7 meters per second to 5.7 meters (roughly 20 kilometers per hour). The sequence of events suggests there were at least 2 and probably turbidity currents involved.  It is probably not a coincidence ...

Heavy rains in Côte d'Ivoire likely caused rivers to dump large amounts of sediment at high speed into the Atlantic. These undersea mud Tsunamis accelerate down the deep gradient of the continental shelf off Abidjan and destroy anything in their path. In particular, they displace the sea floor up to several meters. It is likely that a turbidity current effectively disinterred the WACS trunk and severed it. The main value of WACS is moving traffic between Africa and Europe. So this outage imposes severe hardship on African ISPs. Outages off Côte d'Ivoire's shore are common and have disrupted Internet service in the country many times. For example, in 2024 a debris slide in the subterranean canyon off Abidjan took out four cables, including WACS. Côte d'Ivoire really needs high capacity fibre optic links into neighboring countries to better weather these network crises.

ISPs in Ghana are reporting their 2Africa waves are up and running. So 2Africa's main trunk appears untouched. Hence the Cote d'Ivoire outage must be due to a branching segment fault. It is thought a turbidity wave caused the damage. This is a powerful surge of water, debris, and mud that can wash away the sediment covering buried cables and snap them like toothpicks. I call it an underwater Tsunami. It is triggered by an undersea avalanche due to an earthquake or a flooding river like the Congo pouring into the Atlantic. For example, the 2006 Taiwanese earthquake caused a turbidity current that tore apart 22 cables off the country's Southeast coast. This current traveled several hundred kilometers and reached speeds as high as 72 kilometers an hour. It is not clear what caused the turbidity surge off Abidjan. What we do know is that there is a large subterranean cavern, Le Trou Sans Fond, at Abidjan's doorstep. It was likely involved.  The last few days Cote d'Ivoi...