Monitoring of magmatic-hydrothermal system by noble gas and carbon isotopic compositions of fumarolic gases.

ABSTRACT: We repeatedly measured isotopic compositions of noble gases and CO₂ in volcanic gases sampled at six fumaroles around the Kusatsu-Shirane volcano (Japan) between 2014 and 2021 to detect variations reflecting recent volcanic activity. The synchronous increases in ³He/⁴He at some fumaroles suggest an increase in magmatic gas supply since 2018. The increase in magmatic gas supply is also supported by the temporal variations in ³He/CO₂ ratios and carbon isotopic ratios of CO₂. The ³He/⁴⁰Ar* ratios (⁴⁰Ar*: magmatic ⁴⁰Ar) show significant increases in the period of high ³He/⁴He ratios. The temporal variation in ³He/⁴⁰Ar* ratios may reflect chan

SUBMITTER: Obase T 

PROVIDER: S-EPMC9678900 | biostudies-literature | 2022 Nov

REPOSITORIES: biostudies-literature