Water samplings and the chemical analysis of discolored waters around Osima.
Just after the fissure eruption of Osima Miharayama, widely distributing dense discolored water was discovered near Hude－sima of the southeast coast of Osima on Nov. 22, 1986. As the Hydrographic Department of Maritime Safety Agency has been conducting surveillance and investigation on the activity of submarine volcanoes and volcanic islands, we made chemical analysis of the discolored water appearing around Osima with water samplings by a radio-controlled boat and helicopters from Dec. 1, 1986 in order to distinguish whether discolored water was from volcanic activities or from being contaminated by land materials. A newly designed radio-controlled boat, which could pump up the discolored water of 6 bottles, each 10 L, was constructed and utilized. The boat was ordinarily operated from a helicopter, but sometimes operated from the Osima island when the volcanic activity was low. AXBT measurements to get vertical water temperature profile were carried out when water samplings from a helicopter had been made. Sampled discolored waters were added HC L and suspended materials were soluted in a heating water bath. Analytical methods of Fe, A Q and Si in discolored water are shown as follows: (1) Fe+3 was reduced to Fe+2 by means of NH2OH ・ HC L and the total Fe+2 was produced a color by the addition ofα，α,α'-dipyridyl and measured with spectrophotometer. (2) AQ was dilut巴dwith distilled water and measur巴dwith atomic absorption spectrophotometer with graphite furnace atomizer.
| Main Authors: | , , , , , , , , |
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| Format: | Journal Contribution biblioteca |
| Language: | Japanese |
| Published: |
1987
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| Online Access: | http://hdl.handle.net/1834/16119 |
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