is a broad pyroclastic plateau in southern Japan. It covers almost all of southern Kyūshū, which was formed by

pyroclastic flow A pyroclastic flow (also known as a pyroclastic density current or a pyroclastic cloud) is a fast-moving current of hot gas and volcanic matter (collectively known as tephra) that flows along the ground away from a volcano at average speeds of b ...

s. It covers more than half of Kagoshima Prefecture, as well as 16% of

Miyazaki Prefecture is a Prefectures of Japan, prefecture of Japan located on the island of Kyūshū. Miyazaki Prefecture has a population of 1,073,054 (1 June 2019) and has a geographic area of 7,735 Square kilometre, km2 (2,986 sq mi). Miyazaki Prefecture borders ...

.寺園貞夫　「シラスの堆積とその浸食地形」　『シラス台地研究』 The Japanese Shirasu (シラス) is a local name of the pumiceous sediments in Kagoshima Prefecture, Japan. The term has been recommended to be used just for the non-welded

ignimbrite Ignimbrite is a type of volcanic rock, consisting of hardened tuff. Ignimbrites form from the deposits of pyroclastic flows, which are a hot suspension of particles and gases flowing rapidly from a volcano, driven by being denser than the surro ...

component in the Japanese geological literature. Daichi (台地) means plateau.

Geology

A major three phase eruption of the

Aira Caldera Aira Caldera is a gigantic volcanic caldera that is located on the southern end of Kyushu, Japan. It is believed to have been formed about 30,000 years ago with a succession of pyroclastic surges. It is currently the place of residence to over ...

formed in the first phase the Osumi pumice fall, had a second phase Tsumaya pyroclastic flow and in the third Ito eruption phase produced the widely distributed Aira-Tn tephra that has been dated at 29,428 to 30,148 years calibrated before present. The Aira-Tn tephra falls from this eruption were up to thick extending to significant depth that would have affected plant life in south eastern South Korea and Honshu. This and Ito Ignimbrite up to thick, are the most significant pyroclastic deposits of the plateau. However an eruption about 11,000 years before present did result in the Satsuma

pumice Pumice (), called pumicite in its powdered or dust form, is a volcanic rock that consists of highly vesicular rough-textured volcanic glass, which may or may not contain crystals. It is typically light-colored. Scoria is another vesicular v ...

fall and there have been multiple relatively minor ash falls since from the local active volcanoes.

References

{{Kagoshima-geo-stub Volcanic plateaus Pyroclastic plateaus Volcanoes of Kyushu Landforms of Miyazaki Prefecture Landforms of Kagoshima Prefecture