What's the likelihood of an eruption?
Impossible to tell from here. Local experts could venture an opinion (sometimes there is some cyclicity to these things) but I suspect the answer would be 'low'.
But it wouldn't go off like Krakatoa overnight. Before any eruption, the liquids and gasses have to make their way up from the magma chamber prob a few km below. This would be evidenced by earthquakes of increasing intensity (talking 1-4 maybe, so just a quiver) for maybe several weeks. Then might go quiet & start again weeks later.
At some stage there would probably be a bulge on the side or near top and/or some more violent earthquakes. Finally, if it was going to 'blow' you might get a day's warning. Might get ... hopefully....
The magma would be silica rich, therefore 'sticky'. That means it would finally go off with a bang (like Mt St Helens) not a whimper (like Iceland).
Nuee ardants..
That second one is not a nuee ardant - they are red/white hot as they flow down the mountainside.
The ash, being silicic would also be very angular and abrasive. Given that Shinjuku in the map is the middle of Tokyo, it would be curtains for a lot of moving infrastructure.
Just checking Japan earthquake app. Its OK
