Upper crustal shear wave velocity and radial anisotropy beneath Jeju Island volcanoes from ambient noise tomography

A study reveals the upper crustal structure beneath Jeju Island, uncovering distinct layers of magma plumbing systems that explain its volcanic evolution. Using ambient noise tomography and transdimensional hierarchical Bayesian inversions, researchers identified negative radial anisotropy (VSH < VSV) at shallow (<2 km) and deep (>5 km) depths, attributed to dyke swarms and vertical magma supply systems, respectively. A notable positive anisotropic layer (VSH > VSV, up to 5%) at mid-depths (2–5 km) suggests horizontally aligned sills, while beneath Mt Halla, the largest central crater, a locally high-temperature body underlies a cooled sill complex. This structure elucidates Jeju Island's volcanic activity, characterized by island-forming lava flows and central eruptions, both before and after cinder cone eruptions.

Lee, S.-J., Kim, S., Rhie, J., Kang, T.-S., & Kim, Y. (2021). Upper crustal shear wave velocity and radial anisotropy beneath Jeju Island volcanoes from ambient noise tomography. Geophysical Journal International, 225(2), 1332–1348. https://doi.org/10.1093/gji/ggab026