Thermodynamic dataset of Shinmoedake magma

by Isoji Miyagi (GSJ)

This is the back data of Miyagi et al. (2025), from which pre-eruptive magmatic temperatures for the 2011, 2018, and 2025 Shinmoedake eruptions have been estimated. A series of thermodynamic data has been obtained using the Rhyolite-MELTS software on the magma compositions of Shinmoedake volcano. The results are visualized as contour diagrams plotted on temperature–pressure planes comprising approximately 53,347 PNG images. These diagrams are interlinked via hypertext, and the associated numerical data are organized in an SQLite3 database, with guidance on extracting relevant information.

Click here to start

The parameters include the amount and chemical compositions of minerals and melt in equilibrium at some P, T, fO₂, and H₂O concentrations. These parameters were obtained using the Rhyolite-MELTS (v 1.1.0) program (Gualda et al., 2012; Asimow and Ghiorso, 1998; Ghiorso and Sack, 1995) over the range of pressure from 1 atmosphere to 860 MPa with 1-10 MPa step, temperature from 700 to 1400 deg-C with 1 deg-C step, oxygen fugacity FMQ+1 log unit, water concentration 0.0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4, 1.6, 1.8, 2.0; 2.2, 2.4, 2.6, 2.8, 3.0, 3.2, 3.4, 3.6, 3.8, 4.0, 4.2, 4.4, 4.6, 4.8, 5.0, 5.2, 5.4, 5.6, 5.8, 6.0, 6.2, 6.4, 6.6, 6.8, 7.0, 7.2, 7.4, 7.6, 7.8, 8.0 wt.% H ₂ O, and CO₂ 0.001, 0.01, 0.1, and 1 wt.%. Since the Rhyolite-MELTS program outputs huge quantities of numerical values, I summarized them into a suite of contour maps on a pressure-temperature plane using the GMT program (Wessel and Smith, 1998) and utilized them cross-linked to develop a convenient tool.

In addition, you can extract numerical data from the plot using the sqlite3 command, following the Command Tips on the graph pages.

Starting material of the MELTS computations

No.	SiO₂	TiO₂	Al₂O₃	tFeO	MnO	MgO	CaO	Na₂O	K₂O	P₂O₅	S	Cl	F	Total	what	Comment
2018-1VGP_18-1V-p14i1	60.801	0.933	17.176	7.089	0.15	1.461	5.605	3.96	2.825		0.066	0.105		100.171	MI in Cpx from 2018 pumice	Saito et al., 2023
MG133_057	62.278	0.948	15.112	8.276	0.143	2.452	5.232	3.295	2.09	0.175				100.001	MG of 4 July 2025 ash	This study
2011-3SGP	61.261	0.587	18.615	4.892	0.098	1.945	7.141	3.416	2.045		0.003	0.054		100.057	GM of 2011 pumice	Saito et al., 2023

MI: Melt inclusions. MG: Matrix glass. GM: Groundmass (glass + fine crystals).

An example of citation:

Miyagi (2025) Thermodynamic dataset of Shinmoedake magma, Kirishima volcano, Kyushu Japan. https://doi.org/10.57765/2003416

References:

Asimow, P., Ghiorso, M., 1998. Algorithmic modifications extending melts to calculate subsolidus phase relations. American Mineralogist 83, 1127–1131. https://doi.org/10.2138/am-1998-9-1022
Ghiorso, M. S., Sack, R. O., 1995. Chemical mass transfer in magmatic processes iv. a revised and internally consistent thermodynamic model for the interpolation and extrapolation of liquid-solid equilibria in magmatic systems at elevated temperatures and pressures. Contributions to Mineralogy and Petrology 119, 197–212. https://doi.org/10.1007/BF00307281
Gualda, G. A. R., Ghiorso, M. S., Lemons, R. V., and Carley, T. L., 2012. Rhyolite-MELTS: a Modified Calibration of MELTS Optimized for Silica-rich, Fluid-bearing Magmatic Systems. J. Petrol., 53(5):875–890. https://doi.org/10.1093/petrology/egr080
Miyagi, I., Konoo, T., Matsumoto, K., Ikenaga, Y., Oikawa, T., Furukawa, R., Iwahashi, K., Araya, N., Takarada, S., Kusano, Y., Tomiya, A., and Saito, G. (2025). Mineral and glass chemical composition of volcanic ash from the eruptions of Shinmoedake, Kirishima volcano on July 2-4, 2025. Poster presentation at the 2025 Fall Meeting of the Volcanological Society of Japan. P75. (in Japanese) #translated summary
Saito, G., Oikawa, T., and Ishizuka, O. (2023). Magma ascent and degassing processes of the 2011 and 2017-18 eruptions of Shinmoedake in Kirishima volcano group, Japan, based on petrological characteristics and volatile content of magmas. Earth, Planets and Space, 75(89):1–39. https://doi.org/10.1186/s40623-023-01836-1
Suzuki, Y., Yasuda, A., Hokanishi, N., Kaneko, T., Nakada, S., and Fujii, T. (2013). Syneruptive deep magma transfer and shallow magma remobilization during the 2011 eruption of Shinmoedake, Japan—Constraints from melt inclusions and phase equilibria experiments. Journal of Volcanology and Geothermal Research, 257:184–204. https://doi.org/10.1016/j.jvolgeores.2013.03.017
Wessel, P., Smith, W., 1998. New, improved version of generic mapping tools released. EOS Trans. Amer. Geophys. U. 79 (47), 579. https://doi.org/10.1029/98EO00426

Version history:

January 2026: Initial release

If you have questions about this page, contact Isoji MIYAGI