| Title | Coupled Integrated Multiphysics approach to quantify Volcanics and Geothermal processes |
|---|---|
| Authors | Gresse, M., Renaud T., Takuto, M., Koyama T., Utsugi, M., Kanda, K., Uyeshima, M. |
| Year | 2026 |
| Conference | World Geothermal Congress |
| Keywords | |
| Abstract | The Aso caldera, Kyushu Island, Japan, is one of the largest volcanic complexes on Earth. Its most active feature, the Nakadake Crater, produces cyclic phreatomagmatic eruptions (e.g., 2015, 2016, 2019, 2021). Ongoing research aims to monitor this volcano to improve understanding of its activity and enhance public safety. Magnetotellurics (MT) methods measures subsurface electrical conductivity which indirectly reflects rock and fluid properties. Heat and Mass Flow simulators are used to characterize the pathways for fluids, formation permeabilities and heat sources driving geothermal processes. This study aims at constraining quantitatively the subsurface properties by combining an electrical resistivity model with a geothermal flow simulator using an inverse fluid flow modeling approach. Based on a conceptual model of Nakadake Volcano, an initial heat and mass flow simulation was created to match the overall electrical resistivity structure. Using modified Archie’s law, rock and fluid parameters (e.g., porosity, permeability, temperature, and salinity) we obtain the calculated electrical resistivity (from the fluid flow simulation), which was then compared to the observed electrical resistivity (from a 3-D MT model). Initial simulation results were used to calibrate the numerical model through automated inversion, significantly improving the fit to observed electrical resistivity data—by a factor of 3 to 4. This approach better constrains the physical properties of rocks in complex volcanic settings and offers a promising new tool for assessing subsurface structures near active volcanoes. The methodology provides a novel integrated framework applicable to geothermal contexts for quantitatively constraining fluid flow and thermal processes by geophysical measurements. |