Imaging of Lithospheric Structure Beneath Jeju Volcanic Island by Teleseismic Traveltime Tomography

Jung Hun Song, Seongryong Kim, Junkee Rhie, Sang Hyun Lee, Young Hee Kim, Tae Seob Kang

Research output: Contribution to journalArticlepeer-review

14 Citations (Scopus)

Abstract

Jeju Island (JI) is an intraplate volcanic field located at the continental margin of Northeast Asia. This volcanic island has been formed by multiple eruptions from the Pleistocene to the Holocene (~3.7 ka), which have yielded hundreds of monogenetic volcanic cones and a central basaltic shield. To understand the volcanic structures and mechanism beneath JI, we deployed 20 broadband temporary seismometers across the island for over two years (October 2013 to November 2015). We investigated the crustal and upper mantle structures in JI for the first time using the gathered data. Through teleseismic traveltime tomography, we obtained images of the lithospheric structure related to the volcanic system. A major finding was the identification of a prominent low-velocity anomaly (<−0.3 km/s in P wave velocity relative to the surrounding high-velocity region) beneath the summit of the central shield volcano at greater depths (50–60 km), which separates into low-velocity zones at shallower depths (10–45 km). Based on previous geological observations, the anomalies were interpreted as a magmatic system, potentially with partial melting. Moreover, relatively high velocity zones were consistently imaged to the north, east, and west of the island, indicating relatively thick lithospheric structures at the southern margin of the continental lithosphere beneath the Korean Peninsula. Based on the geometries of the imaged structures, we suggest that a focused decompressional melting at sublithospheric depths and complex magma interactions within the lithosphere resulted in the characteristics of JI volcanism as intraplate magmatic activities that are isolated in space and confined in time.

Original languageEnglish
Pages (from-to)6784-6801
Number of pages18
JournalJournal of Geophysical Research: Solid Earth
Volume123
Issue number8
DOIs
Publication statusPublished - 2018 Aug
Externally publishedYes

Keywords

  • decompressional melting
  • dispersed magmatic structure
  • intraplate volcano
  • Jeju Island
  • lithospheric structure
  • teleseismic traveltime tomography

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

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