1. Faculty of Geography, Universitas Muhammadiyah Surakarta, Central Java, Indonesia
2. Graduate School of Maritime Sciences, Laboratory of Volcanic Risks at Sea Kobe University, Kobe, Japan
3. Geography Department, School of Science, University of Canterbury, Christchurch,New Zealand
4. Geography Faculty, Universitas Gadjah Mada, Yogyakarta, Indonesia
5. Department of Soil Science, Faculty of Agriculture, Universitas Gadjah Mada, Yogyakarta, Indonesia