[O-08] Poster presentations by senior high school students

[O08-P02] Study on the relationship between partial lunar eclipse and large volcanic eruption

*Riko Tagata¹, *Emika Okamura¹, *Kazuya Hiyamizu¹, Kaede Yoshimitsu¹, Shuka Araki¹, Ayaka Nakashima¹, Masyu Yamasako¹, Akito Nakagama¹, Kohaku Yamaguchi¹, Yuma Furue¹, Seiya Yamagami¹, Ryoma Noda¹ (1.Kokubu High School)

Keywords:lunar eclipse, Volcanic Explosivity Index, Dungeon scale, Turquoise fringe

The partial lunar eclipse on November 19, 2021 was observed by a reflection astronomical telescope and photographed by a digital single-lens reflex camera. Brightness during a total lunar eclipse is thought to be related to the most recent volcanic eruption. A major volcanic eruption is expressed by the Volcanic Explosion Index (VEI). As for past lunar eclipses and volcanic eruptions, it is known that the massive eruption of El Chichon in Mexico in 1982 (VEI = 5), the total lunar eclipse of December 30, 1982, and the massive eruption of Pinatubo in the Philippines in 1991 (VEI = 6) were very dark total lunar eclipses with the brightness of L = 0 and L = 1 on the dungeon scale, respectively, because a large number of volcanic ash particles emitted by the volcanic eruption reached the stratosphere above them in June 3, 1993. Between August 13, 2021 and 15th, Fukutokuokanoba Volcano, an underwater volcano south of the Ogasawara Islands and Iwo Jima, erupted violently with pumice (VEI = 4). The smoke reached an altitude of 19 km, and it was estimated that a large amount of fine volcanic ash particles were released into the stratosphere. Therefore, the partial lunar eclipse this time was expected to be dark red with L = 1 or 2, but the actual lunar eclipse was brighter than that and L = 3 (bright red) on the dungeon scale. The reason for this is that the massive eruption of Fukutoku Okanoba Volcano was an undersea volcano eruption, and it is thought that a large amount of volcanic ash that was spewed out after the eruption of the volcano was disturbed by sea water and did not reach the stratosphere. On January 15, 2022, a submarine volcano in Tonga erupted violently. At VEI = 6, the height of the plume was very large at 58 km. The total lunar eclipse on November 8, 2022 is expected to be quite dark at around L = 0 ~ 1 because it is a very large eruption, although it is an underwater volcano eruption. We will confirm this prediction by observing the lunar eclipse on the day. Turquoise fringe is a phenomenon that has recently become a topic of conversation during a lunar eclipse. During a lunar eclipse, when sunlight passes through the stratosphere, the ozone layer in the stratosphere absorbs red light, and blue light is selectively enhanced. This suggests that the concentration of the ozone layer in the Earth's stratosphere during a lunar eclipse is related to the visibility of turquoise fringes during a lunar eclipse. The partial lunar eclipse of 2021 was bright, but the turquoise fringe was less visible. This may have been caused by the disturbance of the stratospheric ozone layer by the massive eruption of the Fukutoku Okanoba volcano. Therefore, the next total lunar eclipse on November 8, 2022 will not only be dark, but also the turquoise fringe will be hard to see.