A5079903769- Geophysical and Geoelectrical Methods
- Seismic Waves and Analysis
- Geophysical Methods and Applications
- Underwater Acoustics Research
- Seismic Imaging and Inversion Techniques
- Aerodynamics and Fluid Dynamics Research
- Geological and Geophysical Studies
- Advanced ceramic materials synthesis
- Soil Geostatistics and Mapping
- Geochemistry and Geologic Mapping
- School Health and Nursing Education
- Surfactants and Colloidal Systems
- Numerical methods in engineering
- Underwater Vehicles and Communication Systems
- Railway Engineering and Dynamics
- NMR spectroscopy and applications
- Innovative Microfluidic and Catalytic Techniques Innovation
- Oil and Gas Production Techniques
- Cavitation Phenomena in Pumps
- Health Education and Validation
- Non-Destructive Testing Techniques
- Lattice Boltzmann Simulation Studies
- Electrohydrodynamics and Fluid Dynamics
- Fluid Dynamics Simulations and Interactions
- Geological and Geochemical Analysis
Kyoto University
2015-2025
University of Hyogo
2022-2025
Kyushu University
2025
Tokyo Institute of Technology
2021-2024
Japan Agency for Marine-Earth Science and Technology
2022-2024
Graduate School USA
2015
Mie University
2011-2012
Blurred resistivity boundaries resulting from smoothness-regularized inversions of electrical tomography (ERT) data can lead to inaccurate interpretations sharp boundary structures. To address this issue, various ERT inversion algorithms have introduced localized adjustments (localized discontinuities) in the regularization operator at positions where are anticipated. Current approaches rely on prior information about locations, obtained complementary geophysical, geological, and drilling...
Abstract Although seafloor massive sulfide (SMS) deposits are crucially important metal resources that contain high‐grade metals such as copper, lead, and zinc, their internal structures generation mechanisms remain unclear. This study obtained detailed near‐seafloor images of electrical resistivity in a hydrothermal field off Okinawa, southwestern Japan, using deep‐towed marine tomography. The image clarified semi‐layered structure, interpreted SMS exposed on the seafloor, another...
Deep-sea massive sulfide deposits formed by hydrothermal fluid circulation are potential metal resources. They can exist not only as mound manifestations on the seafloor (seafloor sulfides) but also embedded anomalies buried beneath (embedded sulfides). The distribution of sulfides is largely unknown, despite their expected high economic value. Recent drilling surveys have revealed a complex model suggesting coexist sulfides. In coexisting case, geophysical methods required to distinguish...
Abstract Fluids within the Earth's crust may exist under supercritical conditions (i.e., >374°C and >22.1 MPa for pure water). Supercritical geothermal reservoirs at depths of 2–10 km below surface in northeastern (NE) Japan mainly consist magmatic fluids that exsolved from melt during course fractional crystallization. have received attention as next‐generation resources because they can offer significantly more energy than obtained conventional found temperatures <350°C. However,...
Coastal freshwater provides a water source for more than one billion people living in coastal regions. For sustainable groundwater management areas, an understanding of distribution is necessary. Freshwater area can extend across the shoreline and into offshore region. Offshore-onshore mapping helps us to gain comprehensive areas. Resistivity imaging using electromagnetic methods has been used reveal areas because electrical resistivity these settings primarily controlled by porosity...
Abstract Near-seafloor concentrated gas hydrates (GHs) containing large amounts of methane have been identified at various chimney sites. Although understanding the spatial distribution GHs is fundamental for assessing their dissociation impact on aggravating global warming and resource potential, within chimneys remains unclear. Here, we estimate subseafloor a site in Japan Sea using marine electrical resistivity tomography data. The resulting two-dimensional structure shows high anomalies...
A 3D marine controlled-source electromagnetic (CSEM) survey for mapping hydrocarbons uses dozens of ocean-bottom electric (OBE) receivers deployed in a grid pattern and several transmitter towlines. This study considers seafloor massive sulfides (SMS) exploration, the horizontal scale SMS is few kilometers, which small compared with hydrocarbon surveys tens kilometers. If we apply CSEM using receiver deployment on grids to map SMS, high costs will be incurred despite size. We have developed...
SUMMARY Although controlled-source electromagnetic (CSEM) methods have higher sensitivity to thin resistive bodies than the magnetotelluric (MT) method, their delineation by inversion requires CSEM data with high signal-to-noise ratio (SNR). This study aims enhance SNR of increasing number stacks. To efficiently stack long-term data, we use an EM-accurately controlled, routinely operated signal system (ACROSS), which can transmit accurately controlled waveforms synchronizing transmitting a...
SMS (Seafloor Massive Sulfide) deposits, including rare and precious metals, have been often found out in the vicinity of hydrothermal active areas: for example Okinawa Trough, Izu-Bonin arc, Azores triple junction mid-Atlantic ridge. Geophysical explorations with electromagnetic (EM) methods are recently carried around deposits Papua New Guinea because known as low resistivity material. The distribution below seafloor can be a good indicator buried deposits. However, structure areas has not...
Earth and Space Science Open Archive This work has been accepted for publication in Other. Version of RecordESSOAr is a venue early communication or feedback before peer review. Data may be preliminary. Learn more about preprints. preprintOpen AccessYou are viewing the latest version by default [v1]3-D resistivity imaging supercritical geothermal system Sengan region, NE...
熱水活動に伴って形成される海底熱水鉱床は，新たな金属資源として注目されている。熱水鉱床は低比抵抗を示すため，海底熱水活動及び海底熱水鉱床の分布調査に海底電気・電磁探査が用いられてきた。しかしながら，これまでに熱水地域で行われた海底電気・電磁探査は簡易的なものに限られており，海底下の広域比抵抗断面の可視化方法は確立されていない。そこで本研究では，深海曳航式電気探査に注目し，熱水地域における深海曳航式電気探査の有効性を評価した。具体的には，有限差分法とOccam's逆解析法を用いた2次元逆解析コードを作成し，数値シミュレーションに基づいて有効性の検討を行った。
The finite difference method and the element are often used as a numerical calculation of electromagnetic field below surface for forward inverse problem MT method. However, using has difficulty including complicated shape in model like topography underground heterogeneous structure. For overcoming weak point, particle attracts attention users recently. is technique to make discretization with particles not aligned along lattice or mesh. In this study, we performed examination about better...
Numerical solving of flow around the complex-shape body is importance in various scientific fields. But there are problems that it takes too much computational time for interpolation scheme between and grid. In present paper, we propose novel numerical by using Cartesian grid with immersed boundary(IB) method; to treat complex shape easily speed up, improved material points constructing body. By proposed scheme, unsteady a rotating electric fan located inside duct simulated. From visualized...
Hydrothermal circulation of sea water through permeable ocean crust leads to the formation sulfide ore deposits, which have potential for mining. Laboratory measurement rock samples revealed that these deposits low resistivity compared surrounding geological units. Therefore, structure is useful detecting and estimating amounts. However, detailed seafloor has not been obtained. Here, we used deep-towed DC Resistivity data image in Iheya North hydrothermal field, mid-Okinawa Trough. We...
The best pulverization of emulsions that can be achieved using conventional mixing blades is in the micrometer realm. Now, with our new ‘thin‐film spin system’ high‐speed mixer, it possible to attain nanometer particle size distribution now controlled achieve an almost single state. Particles pulverized without being severed, preventing secondary agglomeration after processing. This system also solves many problems common processes.
This paper describes the aerodynamic design process of frontal shape for JR300X, which is prototype next generation high speed train by CJR (Central Japan Railway) aiming operational 350 kilometers per hour. The first step to analyze flow field around existing JR300series CFD (Computational Fluid Dynamics) technology. Based on physical knowledge field, conceptual follows create candidate shapes. geometry improved wind tunnel test as step. shapes are then quantitatively evaluated under actual...