Massive underwater avalanches deliver pollutants to deep sea

A magnitude 7.2 earthquake shook the ocean floor off the coast of Newfoundland, Canada. The farthest cable from the earthquake broke 13 hours and 17 minutes later.

At the time, geologists thought that the cables had been broken by a series of earthquakes, but they now know that the culprit was a massive underwater avalanche.

These gravity-driven currents are a key way of transporting silt to the deep sea with the largest able to carry more silt than all the world's rivers combined. turbidites can be hundreds or even thousands of metres thick and were assumed to be dumped in a single event, until a new model showed that it happens in many episodes.

The finding will help geologists better identify ancient turbidite deposits, which sometimes contain gold, or oil and gas, and understand modern-day turbid currents, which can deliver plastic litter and other pollutants to the deep.