It has been included as a Decade Volcano because of the potential dangers it poses to the voluminous numbers of nearby residents.
Global Volcanism Program
Yamanoi et al. Color measurements of volcanic ash deposits from three different styles of summit activity at Sakurajima volcano, Japan: Conduit processes recorded in color of volcanic ash. Journal of Volcanology and Geothermal Research 178 (1), pp. 81-93