[AHW20-P14] Influence of Hakone volcanic eruption (150629) on the surrounding water environment
Keywords:Mt.Hakone, Eruption, Volcanic product, Owaku marsh, Water quality
1. Introduction
Water resources are abundant in volcanic areas, and grasp of water environmental problems is important for conservation and use. When an eruption occurs, it is conceivable that the surrounding river, groundwater, etc. will be contaminated by components melted from the ejecta. Based on this, in order to grasp the influence of the eruption occurred in Owakudani of Hakone on June 29, 2015, the impact on the surrounding water environment is done once a month.
2. Results and Discussion
2.1. EC · pH of river
In Hayakawa River, EC, pH varied from 200 to 400 μS / cm, 7 to 8, and no noticeable change in value was observed in the investigation after the eruption. In Owakusawa, high EC · low pH of 6,780 μS / cm, pH 2.4 was observed in the investigation immediately after the eruption. Owakusawa's EC tends to decline over time, and after 1608 it is stable at around 3,000 μS / cm. As for pH, it is higher than immediately after the eruption.
2.2. Major dissolved component
In Owakusawa, Cl- tends to decrease as time passes since the eruption. On the other hand, there was no conspicuous decline in SO42-. The ratio of Cl- / SO42- was 1.1 in 1507, but it decreased to 0.2 in 1707. As for the cation ratio, there is little change compared to the anion.
2.3. Rainwater
Although rainwater is sampled at nine points, high EC (maximum 230 μS / cm) and low pH (minimum 3) are observed at the point near Owakudani. In 1604 to 1608, there is a point where the amount of components contained in the collected rainwater has increased, and it can be related to the concentration of the volcanic gas around it.
Water resources are abundant in volcanic areas, and grasp of water environmental problems is important for conservation and use. When an eruption occurs, it is conceivable that the surrounding river, groundwater, etc. will be contaminated by components melted from the ejecta. Based on this, in order to grasp the influence of the eruption occurred in Owakudani of Hakone on June 29, 2015, the impact on the surrounding water environment is done once a month.
2. Results and Discussion
2.1. EC · pH of river
In Hayakawa River, EC, pH varied from 200 to 400 μS / cm, 7 to 8, and no noticeable change in value was observed in the investigation after the eruption. In Owakusawa, high EC · low pH of 6,780 μS / cm, pH 2.4 was observed in the investigation immediately after the eruption. Owakusawa's EC tends to decline over time, and after 1608 it is stable at around 3,000 μS / cm. As for pH, it is higher than immediately after the eruption.
2.2. Major dissolved component
In Owakusawa, Cl- tends to decrease as time passes since the eruption. On the other hand, there was no conspicuous decline in SO42-. The ratio of Cl- / SO42- was 1.1 in 1507, but it decreased to 0.2 in 1707. As for the cation ratio, there is little change compared to the anion.
2.3. Rainwater
Although rainwater is sampled at nine points, high EC (maximum 230 μS / cm) and low pH (minimum 3) are observed at the point near Owakudani. In 1604 to 1608, there is a point where the amount of components contained in the collected rainwater has increased, and it can be related to the concentration of the volcanic gas around it.