Results of evolved gas analysis (EGA) on ash + salt samples from the 15 January 2022 eruption of Hunga volcano, Tonga

These data files contain the results of Evolved Gas Analysis (EGA) on a Mettler-Toledo TGA-DSC 3+ attached to a Pfeiffer Vacuum GSD 320 gas mass spectrometer on ash samples from the 15 January 2022 eruption of Hunga volcano, Tonga. Samples were heated in Nitrogen at a rate of 5 °C/min from 30 to 150 °C for dehydration purposes and then at a rate of 30 °C/min from 150 °C to 1300 °C. During heating, the relative amount of different volatile species (H2O, CO2, SO2, HCl, and H2S, which are extracted from mass-to-charge ratios of 18, 44, 64, 36, and 34, respectively) were recorded by the gas mass spectrometer. Natural samples collected for the analysis were bulk ash material or correspond to a given ash fraction. Particles were unwashed and dried at 40°C before analysis. We compared the signals for natural samples with (i) a mixture of salt-free dense glassy particles, white and dark pumice (HT10), (ii) pure halite, anhydrite, gypsum, calcite and pyrit, (iii) mix between pure magmatic particles (HT10) from (i) and manually added components from (iii).

这些数据文件包含对2022年1月15日汤加洪加火山喷发的火山灰样本进行的演化气体分析（Evolved Gas Analysis，EGA）结果。分析采用梅特勒-托利多（Mettler-Toledo）TGA-DSC 3+热重-差示扫描量热仪，其连接至普发真空（Pfeiffer Vacuum）GSD 320气体质谱仪。样本先在氮气环境中以5°C/分钟的速率从30°C加热至150°C以实现脱水，随后以30°C/分钟的速率从150°C加热至1300°C。加热过程中，气体质谱仪记录了不同挥发性物质（H₂O、CO₂、SO₂、HCl和H₂S，分别对应质荷比18、44、64、36和34）的相对含量。用于分析的天然样本为火山灰整体材料或特定粒级的火山灰组分，颗粒在分析前未经洗涤，并于40°C下干燥。我们将天然样本的信号与以下三类样本的信号进行了对比：(i) 无盐致密玻璃质颗粒、白色及深色浮石的混合物（HT10）；(ii) 纯石盐、硬石膏、石膏、方解石和黄铁矿；(iii) 来自(i)的纯岩浆颗粒（HT10）与来自(ii)的手动添加组分的混合物。