Age and Cultural Influence of the Kikai-Akahoya Eruption as Seen from Archaeological Material in South Kyushu, Japan

Abstract

Applying the age of Kikai-Akahoya eruption to the pottery chronology of the Earliest stage of the Jomon period in Kyushu indicates that the eruption occurred between the old stage of Todoroki-A type pottery and the new stage. Moreover, the making of Todoroki-A type pottery, which had wide distribution in the whole of Kyushu, was not disrupted by the Kikai-Akahoya eruption. In addition, I evaluated the recovery process of the living environment after the Kikai-Akahoya eruption on South Kyushu; most of the southern section received a direct hit of Kikai-Koya pyroclastic flow. We can confirm the condition of the sites only in the northern part of South Kyushu immediately after the Kikai-Akahoya eruption, but it is assumed to have been impossible to live in the southern part of South Kyushu, which was directly affected by Kikai-Koya pyroclastic flow. It seems that the living environment had recovered nearly completely by the middle stage of Todoroki-B type pottery (about 5, 500yrs BP) in almost all the inland part of South Kyushu mainland. But the scales of the sites are poor even in the southernmost end part of the Osumi islands or Satsuma and Osumi Peninsula which are near Kikai caldera and sustained serious volcanic damage. We can also recognize residential stability in the whole of South Kyushu after the phase of Sobata type pottery (about 5, 100yrs BP). Besides, it is likely that forest vegetation which produced nuts was considerably damaged by the Kikai-Akahoya eruption, based on the fact that the rates of polishing stones and saddlequerns in the composition of stone implements which were used for milling nuts is extremely low in deposits from immediately after the eruption in the whole of South Kyushu. It is inferred from the increase in the rate of polishing stones and saddlequerns in composition that forest vegetation recovered after the middle stage of Todoroki-B type pottery, at the latest, in the northern part of South Kyushu, and between the new stage of Todoroki-B type pottery and the phase of Sobata type pottery in the southern part of South Kyushu.