Comparative analysis of geomorphological and geological characteristics of small-scale volcanoes applicable to field guide for Jeju Island gaoheritages

In this study, geomorphological and geological characteristics of 6 small volcanoes in Jeju Island (Ilchulbong, Songaksan, Hanon, Sanbangsan, Seobjikoji and Geum-orm) are analyzed based on field survey and analysis of digital topographic maps, which are applicable to field guide for students and visitors. These volcanic bodies are classified into 5 different types of volcanic landform including tuff cone, tuff ring, maar, lava dome and scoria cone, and distinct from each other by lithology, texture and structure and chemical composition of the rock formation as well as caliber, depth and slope gradient of the crater. It is particularly noteworthy that maar, tuff ring, tuff cone, scoria cone and lava dome are in order of increasing slope gradient of outer rims, but the ratio of crater caliber to volcano diameter is in the reverse order. The formation of a lava dome seems to be influenced mainly by the chemical composition and higher viscosity of magma, but the other types of volcanos are preferably controlled by physical properties of magma and/or external condition (e.g., gas content and water interaction) rather than chemical property of magma. The major results of this study are presented by tables, figures and a flow chart, which will help to understand the diverse nature of volcanic geoheritages of the Jeju Island.