*Arifudin Idrus^1,2、Genki Kaneko³、Ryohei Takahashi³、Cendi D.P. Dana⁴、Sutarto Sutarto⁵、Finlan Adhitya Aldan²、Hinako Sato³、STJ Budi Santoso¹ (1.Indonesian Association of Geologists、2. Department of Geological Engineering, Faculty of Engineering, Universitas Gadjah Mada, Indonesia、3.Department of Earth Resource Science, Faculty of International Resource Sciences, Akita University, Japan、4.School of GeoSciences, The University of Edinburgh, Edinburgh EH9 3FE, United Kingdom、5.Department of Geological Engineering, Universitas Pembangunan Nasional Veteran, Yogyakarta, Indonesia)