NHK’s 7 PM news program featured a story about the possibility of a devastating volcanic eruption in the next 100 years. The report was based on a press conference given by some researchers at Kobe University. The “worst-case scenario” was an eruption of Mt. Aso on a scale that produced the caldera (the valley) tourists go to the area to view. According to that scenario, pyroclastic flows would cover much of Kyushu and up to about 50 centimeters of volcanic ash would cover an area extending to Kobe.
The researchers seem to be arguing that there is a 1% possibility that such an event (though not necessarily in Kyushu) could occur in Japan in the next 100 years and that there is a need to do more research on the prediction of such events and what steps might be taken to limit the extent of the damage.
http://www3.nhk.or.jp/news/html/20141022/k10015614021000.html