Characters of Tephra Layer Deposited by 2011 Shinmoe-dake Eruption in Kirishima Volcano

Abstract

Shinmoe-dake, one of a crater of Kirishima volcano, occured severe eruptions on Jan. 26-27 in 2011. The Tephra derived from this eruption, deposited eastern side of Kirishima Volcano, and formed a new tephra layer. The layer mainly conformed from pumice and more than 90% particle is larger than 1phai. The fine particle, smaller than 1phai has a tendency to increase southern side from the main tephra axis.
The Tephra layer shrunk slitly from Feb.6 to March 6, but add the thickness from March 6 to June 4 by bioturbation. This phenomena shows the soil formation process started in 4 month.