/technologies/sensor-technology/b/blog/posts/scientists-identify-unusual-signal-that-reverberated-around-the-world-for-nine-daysThe seismic activity was the result of a massive landslide in Greenland's Dickson Fjord, which caused a 200-meter-high mega-tsunami that sloshed back and forth roughly 10,000 times in nine days. (Image credit: Wikipedia ) On September 16, 2020, ...en-USTelligent Community 12