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Affiliation |
Graduate School of Engineering Science Department of Systems Design Engineering Civil and Environmental Engineering Course |
AMITA Kazuhiro
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Graduating School 【 display / non-display 】
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1991.04-1995.03
Kochi University Faculty of Science Graduated
Graduate School 【 display / non-display 】
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-2003.03
Kyoto University Graduate School, Division of Natural Science Doctor's Course Completed
Campus Career 【 display / non-display 】
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2018.04-Now
Akita University Graduate School of Engineering Science Department of Systems Design Engineering Civil and Environmental Engineering Course Assistant Professor
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2016.04-2018.03
Akita University Graduate School of Engineering Science Research Center for Engineering Science Assistant Professor
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2014.04-2016.03
Akita University Graduate School of Engineering and Resource Science Research Center for Engineering Science Assistant Professor
Research Areas 【 display / non-display 】
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Natural Science / Atmospheric and hydrospheric sciences / 水資源・地表環境学
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Environmental Science/Agriculture Science / Environmental impact assessment
Research Achievements 【 display / non-display 】
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Prototype geochemical towing observation system for detection of coastal seafloor discharge of volcanic fluids and its evaluation of performance at volcanic CO<sub>2</sub> upwelling area
OHSAWA Shinji, AMITA Kazuhiro, MISHIMA Taketoshi, SAITO Kei, MASAMOTO Futo, TAKAHASHI Hiroshi, MORIKAWA Noritoshi
Journal of Japanese Association of Hydrological Sciences ( THE JAPANESE ASSOCIATION OF HYDOROLOGICAL SCIENCES ) 52 ( 3 ) 107 - 121 2022.12
<p>A prototype “Geochemical Towing Observation System" was developed to detect the presence of volcanic fluids discharging from the coastal seafloor in shallow waters from the sea. We confirmed the stable operation of the observation system and evaluated its ability to detect volcanic fluid discharge in one of the coastal waters of Himeshima Island (Oita Prefecture, Japan), where volcanic CO<sub>2</sub> gas has been discharged from the seafloor. In the observed sea area, as the concentration of dissolved inorganic carbon (DIC) in seawater increases, its δ<sup>13</sup>C value changes toward the estimated δ<sup>13</sup>C of volcanic CO<sub>2</sub>, so we believe that the observation system has successfully captured the seafloor discharge of volcanic fluids. In addition to DIC, a significant change in redox potential (ORP/Eh) also appeared, which can be explained by the detection of H<sub>2</sub>S dissolved in seawater contained in seafloor gases. Combined measurements of <sup>222</sup>Rn, salinity corresponding to electric conductivity, and water temperature, which have been effective in detecting submarine groundwater and hot spring water discharges from the seafloor in the Beppu Hot Springs coastal area in the back of Beppu Bay, showed no expected changes. This may indicate that submarine groundwater discharge from the seafloor along the coast of Himeshima Island is not significant and that gas discharge is the main cause.</p>
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STUDY ON IMPROVEMENT OF TAMAGAWA ACIDIC WATER USING FLY ASH GRANUTRALIZER
SAITO Noritoshi, KAGAYA Fumito, IKEUCHI Takao, SASAKI Asuka, MINAMIDA Yu, AMITA Kazuhiro
Journal of Japan Society of Civil Engineers, Ser. G (Environmental Research) ( Japan Society of Civil Engineers ) 78 ( 5 ) I_233 - I_238 2022
<p> The Tamagawa acidic water originates from the Tamagawa hot springs in eastern Akita Prefecture. Currently, the pH of Lake Tazawa has increased from 4.6 to about 5.8 due to the operation of a neutralization treatment facility. However, it has not recovered to 6.8, and the water environment and ecosystem have not yet recovered. In this study, a neutralizer was prepared using fly ash to improve Tamagawa acidic water and to expand the use of coal ash. Neutralization experiments were conducted to evaluate the effectiveness of the neutralizer by analyzing pH changes, the neutralizer, and treated water. The results showed that the neutralizer did not disintegrate or leach heavy metal ions in the weakly acidic range, suggesting that the neutralizer could be used stably.</p>
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A study on water balance and water quality improvement in Lake Tazawa
OYAGI Hideo, CHIKITA Kazuhisa, AMITA Kazuhiro, Fujii Tomoyasu
Proceedings of the General Meeting of the Association of Japanese Geographers ( The Association of Japanese Geographers ) 2020 ( 0 ) 2020
<p>A study on water balance and water quality improvement in Lake Tazawa</p>
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Chemical and Isotopic Compositions of Fumarolic Gases from Yakedake Volcano, Japan
SAITO Takeshi, SAWAMURA Shun, TAMURA Rina, SEKI Susumu, AMITA Kazuhiro, MISHIMA Taketoshi, OHSAWA Shinji
BULLETIN OF THE VOLCANOLOGICAL SOCIETY OF JAPAN ( The Volcanological Society of Japan ) 64 ( 1 ) 1 - 9 2019
<p>Since the latest phreatic eruption in 1962-1963, Yakedake volcano has remained dormant, but fumarolic activity around the summit area has continued steadily during the past hundred years. Temperature, chemical, and isotopic compositions of fumarolic gases were ascertained for 2013-2017. Discharge temperatures of the most active fumarole were 113-123°C: much lower temperatures than those during the active period. Lower concentrations of HCl and H<sub>2</sub> and a lower SO<sub>2</sub>/H<sub>2</sub>S ratio coincide with this relative quiescence of the present Yakedake volcano. The apparent equilibrium temperatures estimated from the sulfur reactions were about 250-280°C, which decreased by about 200°Cshortly after the latest eruption and which were lower than the critical temperature of water, suggesting the formation of a volcanic hydrothermal system beneath the summit region. The isotopic compositions of water (D,<sup>18</sup>O) show that the fumarolic fluids were probably formed by mixing of the magmatic fluids and local meteoric water. The contribution of magmatic fluid to the sampled fumarolic fluids was estimated as about 80-90%, which is higher than the values obtained shortly after the latest eruption. The estimated volcanic hydrothermal system under the volcano is possibly less influenced by local meteoric water, in spite of the low discharge temperature and low concentrations of gas species derived from high-temperature volcanic gas.</p>
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Chemical and isotopic compositions of fumarolic gases from Yakedake Volcano, Japan
Sawamura S., Saito T., Amita K., Mishima T., Ohsawa S.
PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN ( The Volcanological Society of Japan ) 2018 ( 0 ) 243 - 243 2018