◆Jomon Times and earthquake disasters -Tsunami dameges and shell-mounds on Miyato Island-
A Jomon Seminar was held at "readers' hall" on 2nd floor, the main building, the Asahi Shimbun head office on January 27, 2012. The theme was "Jomon new era". In the first session Yasuhiro Okada, Aomori Prefectural Board of Education Cultural Properties Protection Division head, delivered a lecture with aiming at World Heritage Entry as its them on current situation and assignments toward Jomon sites world heritage entry, and in the following second session Michio Okamura, an honorary researcher at Nara Institute of Cultural Properties Research, gave a lecture on Jomon Times and earthquake disasters. We report in this issue what Mr. Okamura lectured.
Jomon-like life remained on
Continuing inquiring survey into those who are around eighty years old and investigating gravestones and death register on Miyato Island, Oku-Matsushima, Miyagi Prefecture every month after the huge earthquake disaster, it has gradually become known that islanders life before the rapid economic growth came in the island and in Jomon Times hadn't changed so much. People make use of Satoyama (a village with forest and cultivated fields harmonious with natural features), calling "Murayama (Literally, Village Mountain)" as commons. They had taken charge of "Mura-Ido (Village well)," the best well in the village in a group. Villagers mow saw grasses for repairing roofs all together in rotation. "Ko" groups connect people, arranging funeral ceremonies, graves, festivals and so on through "Ko." I think it's quite Jomon-like.
The reason why I have continued to investigate this kind of things is that it's necessary to probe into history in which the community has been sustained, making earthquake disaster reconstruction. In other words we must feel out how people have survived for several thousand years in and together with abundant natural environment. I think the restoration planning for devastated area will just end in making a cut-and dried new town without such a base.
People survived with the help of history
Many houses were carried away to the sea by the drawback of Tsunami on Miyato Island. Nobiru settlement located to the south of Senseki Line and Touna Canal was utterly destroyed. As many as 346 people died here. In my opinion one of the reasons is that no transmission of Tsunami has been handed down as the location is a new residential area and preparation for disaster hasn't been fully made.
The settlements at Ohama, Murohama, Tsukihama on Miyato Island facing the Pacific Ocean were almost totally destroyed and Satohama settlement where Satohama Shell-mound is located was also heavily damaged. Human casualties were few, however. I think it was because Tsunami sufferings have been handed down, which made residents help together carefully to run away. There is a stone monument called "Sekibutsu (Stone Buddha)" on the island. Islanders said it was a monument of Tsunami in ancient times. There is another place where Tsunami casualties have been handed down. Huge Tsunami including Jogan Tsunami in 869 attacked there several times in the past and the residents repeatedly talked about Tsunami, remembering the damages.
Safety place chosen for living area by Jomon People
There are about 480 shell-mounds on about 400 kilometer seashore between the eastern coastlands, so-called Sanpachi Region in Aomori Prefecture and Iwaki coastlands in Fukushima Prefecture. Shell-mound settlement formed in early Jomon Times is located on about 15 meter high place from sea level. But the sea level at that time was lower than today. Shell-mound settlement in early, middle, and late Jomon Times were located about 20 to 40 meter high from sea level and shell-mound settlement made in very late Jomon Times was about 10 to 15 meter high from sea level. It was cold in very late Jomon Times and the sea level became lower.
Any shell-mound settlements weren't covered with sea water by Tsunami this time. Jomon shell-mound means a dumping ground for garbage at seashore settlements and is located at high place from sea level. Meanwhile, "Hama-Kaizuka (Beach shell-mound)" is located on the beach and was attacked by Tsunami. "Hama-kaizuka" is meant such a place to operate business as Jomon People made it a rule to manufacture dried shellfishes from early Jomon Times when their settlement life became sure and to manufacture salt from seawater with potteries around the end in Jomon Times. In reconstructing the devastated area scholars insist the sufferers should separate business operation from life, for example they should live on the hilltop and operate business on the beach. In Jomon Times I guess such a separation was realized.
Traces of earthquake left on the land
In boring the spot at Nishihata-Kita just in front of Satohama Shell-mound, we found thick sand gravel layer including shells around 4,700 B.C. and the stratum becomes thinner from the sea to the land. It was in the second half of middle Jomon Times, a little later of peak period of Sannai-Maruyama Site. Additionally, a similar stratum was found around 3,130 B.C. It was in the beginning in late Jomon Times when Oyu Stone Circle, Akita Prefecture,was formed. They are considered Tsunami deposit as sand and shells flowed from the sea. Though we considered the possibility that Tsunami attacked Japan at least three times in Jomon Times, we didn't know the extent. As a result we bored various spots on the island after the earthquake disaster of this time, it has gradually become known that Tsunami had often attacked since Jomon Times.
The traces of natural disasters such as sand boil, liquefaction, flood, eruption and so on surely remain in the land. Comparing and checking them with our archaeological diagnosis and observations, we can know the history of natural disasters, situation of damages and so on. We must make the history of natural disasters a lesson.
Toward reconstruction and development of Miyato Island
I think we had better think all together how revitalization of the devastated area should be promoted and how the regional construction should be resumed and advanced, respecting the history and features of the island toward the reconstruction and development of Miyato Island. We grew Jomon buckwheat in September, reaped it in November, made noodles and ate it in January as the first package of reconstruction project in 2011 fiscal year. We plan to hold a panel discussion together with the islanders and the researchers of geological features and vegetation are now investigating to realize it. I'm making folklore investigation and social survey, too. Checking the history of the island totally, I would like to consider how to hand down the special quality of the island to future generation
and how to make regional construction from now on together with urban planning scholars. I consider we should design a new tangible town which connects residents, prevents destruction of natural environment and landscape, following ancient moral teachings and village type. We mustn't reconstruct just "Danchi(estate)".
Next is sightseeing. The second largest industry in the island is "Minshuku (Private houses providing bed and meals like B and B in Britain)." Most of them were washed away and many islanders gave it up. The Historical Museum of Jomon Village Oku-Matsushima is to open in March, 2012. I would like to consider recovery of historical site, Satohama Shell-mound and reconstruction of the devastated area together with islanders.
(Translated by Junzo Miyamoto)