First confirmation by excavation of a house buried by Mt. Fuji eruption over 300 years ago Shizuoka

First confirmation by excavation of a house buried by Mt. Fuji eruption over 300 years ago Shizuoka July 5, 19:35

This is a new discovery about the Hoei eruption that occurred on Mt. Fuji about 300 years ago. For the first time, a part of the house at that time was found in the Subashiri district of Oyama Town, Shizuoka Prefecture, which is said to have been filled with volcanic ash from the eruption. It is highly likely that it was burned by high-temperature pumice due to the fact that it was burnt black, and experts say that it is an important discovery when considering measures for eruption of Mt. Fuji.

At the foot of Mt. Fuji, there was a village of Subashiri Village in the Subashiri district of Oyama Town, Shizuoka Prefecture during the Edo period, but it is said that volcanic ash accumulated about 3 m and was buried by the Hoei eruption in 1707.

Furthermore, since the city is built on it, the records of the settlement in Subashiri Village are only left in old documents, and no home was actually found.

In June of last year, Oyama Town and a research team made up of archaeological and volcanic experts conducted an excavation for the first time to find out how the village of Subashiri Village near the crater was damaged. It was

Initially, the survey was carried out using heavy machinery, and after excavating more than 20 cm, layers of volcanic ash and pumice erupted during the Hoei eruption appeared.

Further digging with human hands, at a depth of about 2 m
, in addition to the two square timbers that can be seen as the "pillars" of the
house, the "walls" and "thatched roofs" of the house Some were found one after another.

This is the first time we have found a house in Subashiri Village that was buried by the Hoei eruption.

In addition, the wood was burnt black, and pumice stone with a reddish interior was also found, so the research team believes that the hot pumice stones from the eruption probably burned the house.

In the future, the research team will proceed with the verification of the stage of the eruption and how the house burned.

Setsuro Kaneko, a member of the Koyama Town Board of Education, who participated in the survey said, "I was so excited that when a burning pillar came out, I was really able to confirm the history of the village, which was only an old document. It is a result. In addition to applying what we learned from the excavation to future disaster prevention, we will continue to make diligent surveys and carefully preserve the ruins."

The research team leader, Kohei Sugiyama, a research fellow at the University of Tokyo, said, "It was demonstrated that the house was burned by the eruption of Mt. Fuji, which is an important clue when considering eruption countermeasures."

Subashiri area covered with thick volcanic ash

The Hoei eruption started in the middle of the Edo era, about 300 years ago, on December 16, 1707, on the eastern flank of Mt. Fuji, and continued until January 1 of the following year.

It is said that the oldest documents were the most damaged in the subashiri village at the foot of the Hoei crater, which is about 10 kilometers away, and it is located in the current Subashiri district of Oyama Town, Shizuoka Prefecture.

Subashiri Village was a village that spreads in front of the "Fuji Sengen Shrine" at the entrance of the mountain trail to Mt. Fuji.

According to the records of ancient documents, 37 houses were burned down by the fire caused by the hot ejecta, although there were no deaths, and the remaining 39 buildings that were not destroyed due to the weight of the ejecta over 3m and frequent earthquakes. It is said to have collapsed.

Since the entire village was covered with thick volcanic ash, it was hardly removed, and a new town was rebuilt on top of it, and the buried houses were a tradition without being found.

It is highly likely that Mt.Fuji will erupt in the future due to past occurrence cycles, etc.It is important to consider the damage caused by the last Hoei eruption in order to consider future disaster prevention. The discovery will be noticed.

Yoshihiro Ishibashi, the head priest of Fuji Sengen Shrine in the Odori District of Oyama Town, said, ``I heard from ancient times that there was a town buried under the ground due to an eruption, and I was wondering if this was true. It is scientifically verified by the research conducted by the University of Japan, and I'm glad that we faced the threat of Mt. Fuji's eruption by creating a new town on the volcanic ash that filled the village, so it is a wisdom of old people that we should cherish it I was talking."

Radar survey started excavation of a complex uneven house in the ground

The excavation was carried out by Oyama-cho, Shizuoka Prefecture, a research team of Kohei Sugiyama, a researcher at the University of Tokyo, who specializes in archeology, and Toshitsugu Fujii, an emeritus professor at the University of Tokyo, who specializes in volcanology.

Since 3 years ago, the research team has been conducting radar surveys using radio waves to explore the ground in the Subashiri area, where it is said that there are settlements buried in ancient documents.

As a result, it was confirmed that there were complex irregularities in several vacant lots, and the research team presumed that there was a structure like a house here.

Then, excavation and investigation by heavy equipment and manual work started in this vacant lot. I dug a hole that is 12m long and 3m wide.

After digging about 20 cm from the surface of the earth, eruptive products such as volcanic ash and scoria, which had cooled and solidified as magma foamed, were deposited under a thickness of about 2 m.

In the lowermost layer, about 15 cm of whitish pumice, which seems to have fallen immediately after the eruption, is deposited, and from that, two pieces of wood, which are black and scorched and have a diameter of about 10 cm, are considered to be "pillars", It came out upright.

In the surrounding area, debris like a part of the "wall" or "thatched roof" of the house was found.

Furthermore, from the south side, a field ridge about 50 cm in length and 1 m in width and 10 cm in width was found, and when the soil sampled was examined, it was found that barley was included.

In the past, some of the houses buried by the Hoei eruption were excavated at the Nagasaka Ruins in Gotemba City, Shizuoka Prefecture, but this is the first time that such houses have been confirmed in the Subashiri area where the entire village has been buried. ..

"It was only a legend that Subashiri was buried by an eruption, but it was a great archaeological achievement to prove its existence for the first time," said Sugiyama, a research fellow at the University of Tokyo.