Geodetic evidence for interconnectivity between Aira and Kirishima magmatic systems, Japan

E Brothelande,F Amelung,Z Yunjun,S Wdowinski

doi:10.1038/s41598-018-28026-4

E Brothelande, F Amelung + Show 2 more

Open Access

https://doi.org/10.1038/s41598-018-28026-4

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Abstract

It is not known whether clustered or aligned volcanic edifices at the Earth surface have connected magmatic systems at depth. Previously suggested by geological records of paired eruptions, volcano interconnectivity still lacks proper geodetic evidence. Here we use GPS time-series and deformation modeling to show how Aira caldera and Kirishima, two adjacent volcanic centers in Kagoshima graben (southern Japan), interacted during Kirishima unrest in 2011. Whereas Aira caldera had been inflating steadily for two decades, it deflated during the eruption of Kirishima which started with a large-volume lava extrusion. This deflation, which cannot be explained by stress changes, is interpreted as the result of magma withdrawal from the Aira system during the Kirishima replenishment phase. This study highlights the behavior of connected neighboring volcanic systems before and after a large eruption, and the importance of taking into account volcano interactions in eruption probability models.

Highlights

Recent studies have widely improved our understanding of how volcanoes respond to tectonic[1,2,3,4] and climatic[5,6,7] forcing
We show how the caldera dynamics was affected by the 2011 eruption of its neighbor, using deformation data inferred from permanent GNSS stations in the area (Supplementary Fig. A.1)
We use the length evolution of GPS baselines in Aira caldera area (Fig. 2a), that provide a synthetic view of deformation, to determine whether the magmatic system was affected by the processes associated with the eruption at Kirishima

Summary

Introduction

Recent studies have widely improved our understanding of how volcanoes respond to tectonic[1,2,3,4] and climatic[5,6,7] forcing. Aira caldera and Kirishima volcanic group are located ~22 km away from each other, in the same active graben (Kagoshima, Fig. 1). One of the most active and hazardous volcanoes in South Japan, is associated with an active cone, Sakurajima (Fig. 2a). A Plinian eruption (VEI 4) occurred in 1914, which caused the death of 58 people, after a period of inflation of Aira caldera and was accompanied by ~1-m subsidence of the caldera floor[17,18,19] (Fig. 2b). Kirishima is a group of volcanoes, at the north of Aira, among which Shinmoedake produced two strong magmatic or magmato-phreatic eruptions separated by almost 300 years, in 1716–1717 and in 201121.

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