Mapping aqueous fluids and magmas in the Earth’s interior to reveal their connections with earthquakes and volcanoes
Outline
The research group of Prof. Hikaru Iwamori (The University of Tokyo), Prof. Yasuo Ogawa (Institute of Science Tokyo) and Prof. Tomomi Okada (Tohoku University), in collaboration with Prof. Tohru Watanabe (Faculty of Sustainable Design, University of Toyama) has mapped aqueous fluids and magmas in the Earth’s interior to reveal their connections with earthquakes and volcanoes.
Subsurface geofluids (e.g., aqueous fluids and magmas) drive Earth’s evolution through seismogenesis, volcanism, and plate motion. Mapping geofluids based on geophysical observations is critical to understanding these geodynamic processes.
In this study, we applied a recently developed inversion method to simultaneously analyze seismic velocity and electrical conductivity using high-resolution tomographic results to quantitatively map fluid volume and determine the geometrical parameters of geofluids.
Our result was published in a scientific journal, Communications Earth & Environment, on 22 May, 2025.
Background of Research
Geofluids in the Earth’s interior play important roles in various geodynamic processes. Aqueous fluids expelled from subducting plates can react with the mantle rocks, lowering the melting temperature and producing magma. These aqueous fluids and magmas can rise and result in arc volcanism, seismicity and crustal deformation, and continental crust growth over a long period.
Previous studies employed various observational methods, such as seismic or magnetotelluric (MT) tomography, to elucidate the distribution of geofluids. However, seismic velocity or electrical conductivity alone is insufficient for constraining the distribution of geofluids.
Research Contents and Achievements
We employ a novel inversion method capable of simultaneously analyzing seismic velocity from high-resolution seismic-wave tomography along with electrical conductivity from MT data in a volcanic region of Northeast Japan.
A large, slightly leaking fluid reservoir is identified at a depth of 10-20 km. The fluid pressure-depth profile indicates that the seismogenic region corresponds to the area with the highest excess fluid pressure directly above the reservoir. Magma along the Moho released aqueous fluids, resulting in high pore-fluid pressure that induced earthquakes in the upper crust. Certain magmas ascend to form active volcanoes, leaving behind a magma-depleted zone.
Future Developments
Mapping geofluids in various regions will contribute to long-term evaluations of seismic and volcanic activities and mitigation of disasters from these activities.
Original article information
Journal
Communications Earth & Environment
Journal link
https://www.nature.com/articles/s43247-025-02351-9
Paper title
Geofluid mapping reveals the connection between magmas, fluids, and earthquakes
Authors
Hikaru Iwamori, Yasuo Ogawa, Tomomi Okada, Tohru Watanabe, Hitomi Nakamura, Tatsu Kuwatani, Kenji Nagata, Atsushi Suzuki, Masahiro Ichiki