한국의 화산 연구사와 최신 성과

초록

This paper summarizes the history and the latest outcomes of volcano research in Jejudo, Ulleungdo, Dokdo, and Baekdusan, which are distributed along the territorial periphery of Korea. Recent studies revealed that Jejudo and Ulleungdo, as well as Baekdusan, are active volcanoes that have erupted multiple times during the Holocene, thereby heightening the need for further research on these volcanoes. Jejudo, the birthplace of volcano research in Korea, is a unique volcano whose activity was influenced by the plate movements in the Japanese subduction zone, while it is an intraplate volcano located far from the zone. Having experienced hydrovolcanic activity for a long time under the influence of fluctuating Quaternary sea-levels on a continental shelf, its volcano stratigraphy differs markedly from that of typical oceanic volcanic islands abroad. Due to these unique characteristics, research on Jejudo has reached a world-class level in the fields of intraplate volcanism and hydrovolcanism. Baekdusan is one of the largest volcanoes in East Asia, which made a devastating historical eruption, attracting significant research interest not only from China, Japan, and Russia, but also from the Western countries. However, due to Baekdusan's geopolitical location, research by Korean geologists has inevitably been very limited. A notable recent research case includes the world-first discovery of "bubble pocket" structures in pumice from the Baekdusan's Millennium Eruption, which contributed to increase the explosivity of the magma during the eruption. Ulleungdo and Dokdo are oceanic volcanic islands in the East Sea with poor accessibility. Research on these islands therefore began very late, with their geological maps first published in 2012. Both islands were formed through basaltic submarine volcanism, followed by explosive trachyte volcanic activity. In the case of Ulleungdo, there were a total of five explosive eruptions over the past 19,000 years, and some of the erupted volcanic ash was carried to the Japanese Arc. In the case of Dokdo, after a basaltic volcano was formed by submarine volcanic activity during the Pliocene, explosive trachytic eruptions occurred in the Early Quaternary (around 2.5 million years ago), leading to the sequential, underwater to subaerial deposition of the pumice-bearing basaltic breccia (Dongdo Tuff) and the trachytic breccia and tuff (Seodo Tuff). Afterwards, volcanic activity continued on land and under the sea until the Middle Quaternary (hundreds of thousands of years ago). The volcanic edifice of Dokdo has transformed into a flat-topped seamount due to long-term erosion and subsidence. The current island is expected to disappear within a few tens of thousands of years.

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