In March 2018 I visited Mt Hakone when family came to Japan to visit. One of the places we went to was the Mt Fuji area. We went to Lake Ashi on one of those touristy pirate ship cruises. We then went on a cable car up to the Mt Hakone caldera visitor centre. While there, we saw lots of warning signs, including ones that said that if sirens went off, we should evacuate the mountain immediately. However, the lines for the cable cars were really long, and that was just a normal, and not even considering people were finishing the day and were all coming down off the mountain yet.
Mt Fuji and Mt Hakone both are considered active volcanoes, just no recent activity that would prevent people from building a visitor’s centre and tourist industry. It was reported that on Saturday the 18th May there were no tremors on Mt Hakone. However, by Sunday 9am there were 21 (Japan Times), and a further 24 through the day. The Japan Meteorological Bureau announced that they closed access to the visitor centre and raised the alert level from 1 to 2, on a scale of 5. Level 1 means “Potential for increased activity”, and they put warning signs everywhere and evacuation sirens. Level 2 is “Do not approach the crater”, Level 3 is “Do not approach the volcano, Level 4 is “Prepare to evacuate the area”, and Level 5 is of course “Run like you’re Samuel L Jackson in a disaster movie” (JMA). At time of writing, not all parts of the JMA English website had been properly updated, but here is the detailed page: https://www.jma.go.jp/en/volcano/forecast_03_20190518171517.html
The last time Mt Hakone is thought to have erupted was some time in the 12th or 13th centuries. The alert level was last raised to 3 in 2015. These images and more are available for sale at https://ablyth.photoshelter.com/