| 研究実績の概要 |
FY26 a model was developed to correct for post-eruption hydration using water speciation (OH and molecular H2O) measured by FTIR. However, accurate measurement of OH, obtained indirectly from total H2O concentration, is essential. FY27 a formula using species-dependent molar absorption coefficients was derived to accurately obtain OH to reconstruct original total H2O contents. Applying this to pumice from Oomurodashi and Kurose-Nishi submarine volcanoes in the Izu Arc gives reconstructed total H2O contents that relate to pumice texture.
A better understanding of silicate peaks that appear on FTIR spectra of rhyolite glass has also been obtained. While these provide a means to estimate glass thickness they also interfere with the molecular H2O peak.
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