1. Division of Science Education, College of EducationDaegu University Gyeongsan Republic of Korea
2. Helmholtz Centre Potsdam, GFZ German Research Centre for Geosciences Potsdam Germany
3. Institute of Physics and AstronomyUniversity of Potsdam Potsdam Germany
4. Department of Earth, Planetary, and Space SciencesUniversity of California Los Angeles CA USA