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[MIS22-03] Taro Plant on August 5, 1783 – Archaeological Excavations of the Field Buried by the 1783 Eruption of Asama Volcano
★Invited Papers
Keywords:1783 eruption of Asama volcano, Archaeological excavations, Taro plant
Plaster casts of stem tuber of taro plant is obtained at a remain of field buried by debris avalanche caused by eruption of Asama volcano on August 5, 1783. The site is in Naganohara town, Gunma prefecture, central Japan, and is located 20 km northeast from the summit crater. Taro plant is native to the south and can be cultivated at fields up to 100 meters above sea level. Taro plants were experimentally cultivated to know growing condition in August or mid-summer. The experiment was carried out at the fields at elevation of 1000, 750, and 280 m. Most major variety of taro plants was used.
The experiment showed that no differentiation of seed potato was observed at the fields located in a cold, high-altitude place. It was suggested that plaster-casted taro plant had been cultivated under the similar condition of a cold, high-altitude place. The climate condition that leads to Great Tenmei famine had been already appeared before burial of a field by debris avalanche. Even considering the pumice fall continued about 10 days before burial, the 1783 eruption of Asama volcano is not the is not the trigger of the famine. The weather condition before the eruption was already bad for cultivation of plants.
It should be noted that famine has the aspect of man-made disasters. There was an extreme argument that the 1783 eruption of Asama volcano triggered Great Tenmei famineas well as the downfall of Tanuma in 1786 and the French Revolution in in 1789. It is necessary to keep a logical view on volcanic eruptions and their effects.
The 1783 eruption of Asama volcano is suggested to have begun in May 5 and lasted for three months. The Laki volcano in Iceland erupted at about the same time. Most of the lava was ejected in the first five month and the eruption continued until 7 February 1784. Total erupted mass for 1783 eruption of Laki volcano was 3.4×1013 and that for 1783 eruption of Asama volcano was 4×1011. The eruption of Laki. The volcanic ash in the atmosphere erupted from Laki volcano gave rise to the “sand-summer” in Europe.
A unit of pumice fall around the northern foot of Asama volcano can be estimated to have occurred on July 17 and July 27-29, 1783. The pumice fall between July 27-29 leached the field where the plaster casts of stem tuber of taro plant was obtained. It can be estimated that there was a interruption in cultivation before the burial on August 5. We can conclude that up to 53% and down to 30% of the fields were not cultivated. There are historical documents that reports that tax exemption due to poor harvest was 35%, or 100% of millet and soybeans, 80% of buckwheat, and 70% of hie and hemp were wiped out.
The observation of stem tuber of taro plant in 1783, which recorded the cross section of the history, should be discussed with the records left in Europe and the U.S.
The experiment showed that no differentiation of seed potato was observed at the fields located in a cold, high-altitude place. It was suggested that plaster-casted taro plant had been cultivated under the similar condition of a cold, high-altitude place. The climate condition that leads to Great Tenmei famine had been already appeared before burial of a field by debris avalanche. Even considering the pumice fall continued about 10 days before burial, the 1783 eruption of Asama volcano is not the is not the trigger of the famine. The weather condition before the eruption was already bad for cultivation of plants.
It should be noted that famine has the aspect of man-made disasters. There was an extreme argument that the 1783 eruption of Asama volcano triggered Great Tenmei famineas well as the downfall of Tanuma in 1786 and the French Revolution in in 1789. It is necessary to keep a logical view on volcanic eruptions and their effects.
The 1783 eruption of Asama volcano is suggested to have begun in May 5 and lasted for three months. The Laki volcano in Iceland erupted at about the same time. Most of the lava was ejected in the first five month and the eruption continued until 7 February 1784. Total erupted mass for 1783 eruption of Laki volcano was 3.4×1013 and that for 1783 eruption of Asama volcano was 4×1011. The eruption of Laki. The volcanic ash in the atmosphere erupted from Laki volcano gave rise to the “sand-summer” in Europe.
A unit of pumice fall around the northern foot of Asama volcano can be estimated to have occurred on July 17 and July 27-29, 1783. The pumice fall between July 27-29 leached the field where the plaster casts of stem tuber of taro plant was obtained. It can be estimated that there was a interruption in cultivation before the burial on August 5. We can conclude that up to 53% and down to 30% of the fields were not cultivated. There are historical documents that reports that tax exemption due to poor harvest was 35%, or 100% of millet and soybeans, 80% of buckwheat, and 70% of hie and hemp were wiped out.
The observation of stem tuber of taro plant in 1783, which recorded the cross section of the history, should be discussed with the records left in Europe and the U.S.