“Miyagi Network News” vol.98

~By learning from the Tsunami flooding map~

This is Arata Hirakawa from the Miyagi Network for Preserving Historical Materials.

About 2 years ago, I had the idea of observing the hazard map which indicated the forecast for areas expected to be flooded by the River Abukuma in Iwanuma City located to the south of Sendai City. In Iwanuma City, Oshu (*1) Highway runs through the city and Iwanuma-juku (it can be referred to as Iwanuma old post town) is located. I noticed that the area around the Highway and Iwanuma-juku had been depicted as a non-flooded area compared with other places. From this fact, I was convinced that the old highways and post towns had been chosen and planned based on the idea of trying to avoid the landform which tended to flood. By noticing the landforms and locations of each post town, highway, and castle town from this perspective, it was expected that we could get new knowledge on why they chose these locations.

So as to better grasp the stricken area of the Tsunami, Mr.Yuichi Ebina, a member of staff of the Miyagi Network drew up a map of the Tsunami flooded area. When we gazed at this map together, it brought me to the same conclusion as two years ago.

Look at these 2 maps. One is of Natori City and Iwanuma City, and the other is of Watari town and Yamamoto town located to the south of the former one (expanding version, see →  http://www.hanadataz.jp/td/saigai2011/02natori-iwanuma/natori-iwanuma.htmhttp://www.hanadataz.jp/td/saigai2011/03watari-yamamoto/watari-yamamoto.htm ).

Route 4 is running from SendaiCity to the south, and through Natori City and Iwanuma City. When the route meets the River Abukuma, it is re-routed to the forked road, and one road directs to the south and one to the west. The west road which leads to the Siroishi is called Oshu Highway(Route 4), and the southern road is called Hama Highway (Route 6). Although there are some gaps between the present highways and the old highway in the Edo period(*2) because of the bypass, the present routes mirrored the old ones.

The old highway seemingly runs along the Abukuma Mountains line. There were many post towns along the Oshu Highway, such as Nagamachi-juku, Nakata-juku, Masuda-juku (they are now in Natori City), and Iwanuma-juku. As for the Hama Highway, Watari-juku and Yamashita-juku were along it. When we look at the location of the old post towns and highways on the Map of Tsunami flooded area, almost all of the locations are a little removed from the flooded area. Taking a stand against these facts, I started to suspect that we cannot simply regard the highways in the Edo Period as only running along the skirts of mountains even though it did run on flat ground. Although I had never conceived it in normal times, now I gradually yield to consider that those lands where the old post towns and the highways were planned were chosen with the idea which anticipated the range of the Tsunami flooding zone.

In the Oshu area, the great earthquake and Tsunami occurred in the 16th year of Keicho (*3) (2nd December, 1661). It is said that there were 1783 victims in the Sendai Domain, added to this, along the coastline of Morioka Domain and Tsugaru Domain it also took innumerable human lives. This year is just 400 years after that disaster, and again, victims of the Tsunami number more than 30,000.

Now we cannot research when Watari-juku and Yamashita-juku in Hama Highway were opened, because we can no longer enter my study due to the building being destroyed and almost all of the university library’s books being scattered and unavailable for use. However, along the Oshu Highway, it is said that Nakata-juku, Masuda-juku, and Iwanuma-juku were already existence in 1610 (15th year of Keicho). If so, it can be said that the Keicho Tsunami struck after the establishment of those post towns. Although the flooded area caused by this Tsunami is still uncertain, if the present towns had been established in the same location as the original post towns and highways, it could be said to be marvellous that people in the past chose the perfect place to which to avoid the Tsunami damage.

Although we are considering that those post towns originally existed at the same place, by studying the map of the Tsunami flooded area, we might have to be consider another possibility. That is to say the possibility that people resettled those post towns and highways to the safe area, on the so-called the edge of the mountains which were away from the Tsunami zone, based on their prior experience of the Great Keicho Tsunami. This is indeed a issue worthy of examination.

In the Tokyo Web on 23rd March, it published a shocking testimony by a former employee of the Toshiba Corporation who had designed for the Fukushima nuclear plant. The former employee said that he had suggested to his boss that the plant should be designed to be able to stand a Mag.9 earthquake, however his boss laughed at him, and said “Why are you planning for such an event it only happens once every 1,000 years!”

The earthquake 400 years ago brought about the Great Keicho Tsunami and it took thousands of human lives. The Jogan(*4) Tsunami 1,000 years ago, flooded into Tagajo where the old provincial capital was located, and it was recorded that “the number of drowned victims reached around 1,000”. The words of that Toshiba superior completely ignored the experience from history. Just 40 years later, the Fukushima nuclear plant was struck by the disaster that only occurs every 1,000 years. As a result, many people are now facing a serious crisis. Obviously, this is nothing but a terrible man-made disaster, and as such a disgraceful matter.

As I’ve introduced above, this Tsunami too did not reach the old post towns and highways established in the Edo period. By learning from the fact that our ancestors made use of their experience derived from history should be a lesson to us all.

*1 Oshu(奥州): the old name for whole Tohoku area.

 *2 Edo period : or Tokugawa period. A division of Japanese history which spanned from AD1603 to 1868.

 *3 Keicho : Keicho(慶長) A Japanese era dating from AD1596 to 1615.

 *4 Jogan:Jogan(貞観) A Japanese era dating from AD859 to 887.


About Nerwork for Historical Materials
A volunteer group for preserving Cultural Heritage suffered from natural disasters

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