William. Looking into any relationship between volcanic activity in Kagoshima and Kumamoto resulted in “probably not” - and also a pretty illustration of Aso clearly showing the Tateno gap, created by the same fault that caused the seismic unpleasantness a few years ago, without which the caldera would be a lake. As the schematic shows, the Kagoshima and Beppu-Shimabara graben (a depressed block of land bordered by parallel faults) are distinct, though their relationship with volcanic activity is still unclear. If you have a free afternoon, websurfing this topic is rather interesting.