This footage of Mt. Aso’s continuing eruption is referred to in the following statement:
“An aerial observation on Dec. 23 from an Asahi Shimbun helicopter showed the diameter of the vent, formed at the bottom of the crater and through which magma and rock fragments erupted, having expanded by 30 meters since the eruption to measure about 50 meters.”
http://ajw.asahi.com/article/behind_news/social_affairs/AJ201412240066
