They are fast-moving currents that sweep down submarine canyons, carrying sand and mud into the deep sea. However, there is more to them than just sediment-laden seawater flowing over the sea floor, and they also involve large-scale movements of the sea floor itself. This discovery could help ocean engineers avoid damage to pipelines, communications cables, and other sea floor structures. Geologists have known about turbidity currents since at least 1929, when a large earthquake triggered a violent current that travelled several hundred kilometres and damaged 12 trans-Atlantic communications cables. Turbidity currents are still a threat today, as people place more and more cables, pipelines, and other structures on the sea floor. Turbidity currents are also important to petroleum geologists because they leave behind layers of sediment that comprise some of the world’s largest oil reserves. — Science Daily