1. National Institute of Geological Sciences, College of Science, University of the Philippines, Diliman, Quezon City 1101, the Philippines
2. Marine Science Institute, College of Science, University of the Philippines, Diliman, Quezon City 1101, the Philippines
3. Clermont Université, Université Blaise Pascal, Laboratoire Magmas et Volcans, BP 10448, F-63000 Clermont-Ferrand, France
4. National Institute for Science and Mathematics Education Development, University of the Philippines, Diliman, Quezon City 1101, the Philippines