Based on this expert what can be inferred about nantai?
What expert? Is this what you mean?
Mount Nantai (男体山, Nantai-san) literally "man's body mountain", also called Futara-san (二荒山) is a stratovolcano in the Nikkō National Park in central Honshū, the main island of Japan. It stands at 2,486 m high. A prominent landmark, it can be seen on clear days from as far as the Pacific coast, 100 km away.