I visited Hokkaido in autumn 2017 to witness koyo (autumn colors). One day I travelled to Lake Toya to explore the area. I walked the Kompirayama Walking Trail which starts at the Toyako Visitor Centor. You can see many ruins like destroyed apartments and a whole abandoned highway from the eruption in 2000. You have to visit this place it’s breathtaking to see what’s left once nature hits a civilization. That image is one of the more romantic places at the end of the Kompirayama walking trail. If you decide to visit, visit Japan Guide: https://www.japan-guide.com/e/e6727.html