Author's Organization:Institute of Earth Science,Faculty of Education,Yamaguchi University Koto Junior High School Hiruzen Research Institute,Okayama University of Science Institute of Earth Sciences,Faculty of Liberal Arts,Yamaguchi University
Published: April 15, 1993Received: October 05, 1992Available on J-STAGE: April 11, 2008Accepted: February 08, 1993
Advance online publication: -
Revised: -