I had been ignoring this story since it’s so crazy, but it seems to be popping up more and more so I felt it was time to address it. In short, the folks at “Before It’s News” (and others) have been showing the following screenshot from Google Earth, claiming the lines in the image are from an underwater alien base.
It’s very similar to the story that went around five years ago claiming that the lost city of Atlantis had been found, with similar tracks showing up on the ocean surface. Google wrote a detailed blog post explaining what it really was, which is the same case here:
The scientific explanation is a bit less exotic, but we think it’s still pretty interesting: these marks are what we call “ship tracks.” You see, it’s actually quite hard to measure the depth of the ocean. Sunlight, lasers, and other electromagnetic radiation can travel less than 100 feet below the surface, yet the typical depth in the ocean is more than two and a half miles. Sound waves are more effective. By measuring the time it takes for sound to travel from a ship to the sea floor and back, you can get an idea of how far away the sea floor is. Since this process — known as echosounding — only maps a strip of the sea floor under the ship, the maps it produces often show the path the ship took, hence the “ship tracks.” In this case, the soundings produced by a ship are also about 1% deeper than the data we have in surrounding areas — likely an error — making the tracks stand out more.
I encourage you to read the full entry on that old Lat Long Blog post if you want to really understand how this occurs. Stefan at Ogle Earth also wrote a detailed breakdown of Atlantis years ago which is worth re-reading as well.