You probably already know this, but sonar is useless at high speed due to the amount of noise being generated by the submarine's hull during its passage through the water. So you cannot use sonar to detect the growing undersea volcanic mountain as an obstacle in the ship's path. The only defense the ship has against this type of accident is thorough voyage planning prior to the start.
The board felt the navigation team should have noted evidence of “disturbed water” in the vicinity of the collision site (caused by underwater volcanic activity) in the satellite photographs provided to them prior to the voyage. Had they noticed this and evaluated it properly, the correct action was to replot the high speed course to pass well away from the suspect area.
Thank you for that information.