Already we have an answer: no, it's not.
According to the eggheads at Google, the odd grid array is a visual artifact from the sonar process that spawned the undersea maps. In this case, the lines are caused by the paths of the boats on the surface as they went back and forth taking sonar measurements of the ocean floor.
So no Atlantis this time. But I'll bet Lemuria and Mu are still out there somewhere :-)