Abstract
We report in detail deep-sea sediments around the Japan Trench. We have collected core samples using a piston corer system and a MBARI type corer during the cruises KH-05-3 and KH-07-3 by R/V Hakuho-maru and KR04-08, KR08-10, KR09-16 and KR10-12 by R/V Kairei of Japan Agency for Marine-Earth Science and Technology. We recovered totally sixteen piston core samples and two MBARI type core samples in these cruises before the 2011 Tohoku earthquake. Fourteen coring sites are located on the outer rise on the Pacific plate, and 4 sites are on the landward trench slope. The core sediments are predominantly composed of diatomaceous silty clay interbedded with volcanic ash layers. Physical and magnetic properties of the core sediments, and lithological characteristics of tephras such as the refractive indices of volcanic glass and phenocrysts are reported as well.
