Magmatic Activity Research Group

Magmatic activity research group is conducting research to model various magmatic and volcanic phenomena for forecasting eruption, and evolution of volcanic activity in cooperation with the volcanic activity research group. For volcanic hazard mitigation, it is important to predict the eruption style and its evolution. Recent development of monitoring tools enables detection of precursory phenomena; however, it is still quite difficult to predict eruption style and its evolution. Therefore, we need to know more examples of past eruptive activities to extract common features of eruption style and its evolution and to understand their controlling process and mechanisms. We, magmatic activity research group conduct research to model volcanic phenomena with various approaches including geochemical, petrological analyses, and High-Temperature High-Pressure (HTHP) experiments of eruption products, observation of volcanic gas, electro-magnetic phenomena and ground deformation, various laboratory and numerical experiments, to develop methods to predict evolution of eruptive activities.

Example of high-temperature and high-pressure (HTHP) experiments using eruptive products of caldera-forming eruptions at Towada volcano, Japan. (a) Internally heated gas-pressure vessel (IHPV) used for the experiments, which allows achievement of isostatic pressures of up to ~500 MPa using Ar gas and temperatures of up to 1500℃. (b) Equilibrium phase diagram of a rhyolitic magma based on HTHP experiments. Deep blue zone corresponds to the magma storage conditions of the caldera-forming eruption.

 

Magmatic activity research group also has other IHPVs that can achieve pressures of up to 850 MPa. Using these instruments, we are conducting several studies, including estimations of magma chamber conditions and magma ascent processes, hydrous glass synthesis, and simulation of metamorphic textures.

Member

Akihiko Tomiya (Leader, Group)

I am interested in the mechanism of volcanic eruptions, in particular the beginning and sequence. I am investigating pre-eruptive magmatic processes in magma chambers and volcanic conduits, using petrographical methods, such as: analyzing zoning profiles of phenocrysts (e.g., plagioclase and magnetite) to reveal changes in temperature and pressure or injection of mafic magma; high-pressure melting experiments for estimating pre-eruptive magmatic conditions or magma ascending processes.

Ryunosuke Kazahaya (Senior Researcher)

My main interests are modeling of eruptive activities and/or movement of magma at a depth within a volcano by way of volcanic gases study. Degassing process of magma is crucial to get insights of volcanic activities. Recently I've focused on a linkage between volcanic gas and geophysical data in order to comprehend volcanic phenomena.

Takayuki Nakatani (Senior Researcher)

I utilize high-temperature and high-pressure experimental techniques to investigate the migration and storage of magma and aqueous fluid in the Earth’s interior. Especially, I'm interested in the hydration and dehydration reactions of mantle and crustal rocks in subduction zones and the storage depth of magmas beneath arc volcanoes.

Naoki Araya (Senior Researcher)

My research focuses on the mechanisms of volcanic eruptions, with particular emphasis on processes that trigger eruptions and control eruption styles. The timing of pre-eruptive magmatic processes, such as the supply of high-temperature magma, is constrained by compositional zoning within minerals. In addition, volatile concentrations in glass inclusions hosted by phenocrysts are used to estimate the depth at which magma was stored immediately prior to eruptions.

Kurumi Iwahashi (Researcher)

I specialize in igneous petrology, with particular emphasis on the evolution of magma plumbing systems beneath active volcanoes. My research integrates crystal-scale observations with high-precision geochemical analyses of volcanic rocks to constrain the temperature and composition of magma storage and its evolution. Through these approaches, I investigate magma differentiation, magma recharge processes, and eruption dynamics.

Tatsuya Konoo (Researcher)

Volcanology offers a wide range of approaches, including geological, geophysical, and geochemical methods, and researchers’ interests vary accordingly. In my case, I am particularly focused on the complex processes leading to eruptions, and I aim to unravel these complex eruptive sequences using volcanological and material science techniques. By constructing detailed eruption stratigraphy in the volcanic field and conducting meticulous compositional and textural analyses of volcanic deposits in the laboratory, I seek to infer magma ascent processes and contribute to forecasting branching eruption scenarios. In addition, I am engaged in a commissioned research project on the spatiotemporal evolution of magmatic activity about the Sakurajima–Aira Caldera system.

Marceau Gresse (Researcher) (concurrent)

Geophysical imaging applied to active volcanic/geothermal areas using resistivity, self-potential, and remote sensing methods. Groundwater flow modeling of geothermal systems. My research objective is to develop new multidisciplinary approaches to better understand the subsurface structure in complex hydrogeological environment.

Nobuo Matsushima (Technical Staff)

I conduct geothermal and electromagnetic observations at active volcanoes. Main targets are surface temperature distribution, heat discharge rate, self-potential distribution and resistivity structure. These results are used as boundary conditions for numerical simulations, and modeling of magma-hydrothermal systems at various volcanoes is developed.