不可能的油田神話... 油突然從水道底部湧出

A few weeks ago the Yomiuri News on-line reported the following:

まさか伝承の油田か…水路の底から突然、油湧く

2014年11月01日 14時06分

　盛岡市羽場の水路の底から突然、油が湧きだし、付近の住民を驚かせている。

　盛岡市が吸着マットで回収しているが、発覚から２日たっても止まらない。「石油が湧いた」と話す住民もいるが、原因はわからず、謎を呼んでいる。

　市環境企画課によると、２９日午前９時頃、近所の住民から通報があった。幅約４０センチの水路の底の土から黒い油が湧き出し、一時は木伏川に流れ込んだ。市はオイルフェンスも設置し、下流への流出を防いでいる。回収量から１日７リットル程度が湧出しているとみられる。大量の油を使う施設は今のところ確認されていない。

　付近は田畑の中に住宅や事業所が点在する。近くの２０歳代男性は、少し前から異変を感じていた。メダカの水槽に入れる水を水路でくんでいたが、１０月下旬からメダカが死に始めた。「油がすでに混じっていたのでは」と話す。

　北九州市では今年７月、市中心部を流れる川が油で汚染される騒ぎがあったが、原因は、老朽化した地中の送油管だった。古代から原油が産出される新潟市では、住宅地で石油が湧き出すこともある。

　盛岡市の現場の約２キロ西には「油田(あぶらでん)」という地名がある。リンゴ畑や水田が広がるが、油が出たという伝承がある。地元の下舘正行さん（７３）は「子供の頃、祖父や先生から『昔、油が湧いたらしい』と聞いた」と話す。記録は残っていないが、地名は江戸中期の享保年間にはあったという。

　秋田県にも油田があるが、岩手大の越谷信准教授（地質学）によると、岩手県の平野部は新潟や秋田と地質が異なる。「原油を含む地層は奥羽山脈で確認されているが、盛岡市の平地まで続いていない。自然由来とは考えにくい」と話す。市は採取した油を分析し、原因特定を進めている。

(試譯文)

In Haba of Morioka city oil began to flow out suddenly from below a water-way and residents nearby were surprised.

  Morioka city was collecting the oil by suction mats, but even 2 days had passed since its detection, it did not stop and some residents spoke of "Petroleum spring" too, and called it a mystery becasue not knowing the cause.

  According to the city’s Environmental Planning Division, around 9:00 am on the 29^th (November), there was a report from a resident in the neighborhood that black oil began to flow from the earth below a waterway of about 40 centimeters long, and it flowed into the Kifuse river temporarily. The city installed oil fence so as to prevent its outflow to the down stream. From the collected amount it could be thought that about 7 liters a day were gushing out. Facilities that used a great deal of oil could not be found at this moment.

As for the neighborhood, there were housing and a business establishment in the fields. A man in his 20s living around felt something unusual earlier on. The water that he put into his water tank for killifish was drawn from the water-way, but since the end of October the killifish began to die; he said that "it was already mixed with oil".

  In July this year (2014) in Kitakyushu city, the river which flowed through the city center was troubled by oil pollution. The cause was the aging fuel transporting pipe. Petroleum began to spring out in the city area in Niigata-city where petroleum was produced from antiquity.

  About 2 kilometer west of site in Morioka city there was a place named "Oil Field (Aburaden)". While apple field and a rice paddy were wide spreading, there was folklore that oil had come out. Shimodate Masayuki (73) a local said "around the time as a child, I heard from the grandfather and a teacher that ‘oil seemed to have sprung from the field’". While no record had been left, it was said that there was such a place-name during the Kyoho years in the middle Edo period.

  According to Koshiya Shin the associate professor of Iwate University (Geology), while there was an oil field in Akita prefecture, the plains in Iwate Prefecture are different from Niigata and Akita in geological features. He said that "while the stratum at Ou-sanmyaku was confirmed to have petroleum, it does not extend to the plains in Morioka city. It is difficult to think that oil comes naturally". The city was analyzing the extracted oil and was advancing a specific reason.

It is an interesting situation. I also want to know the reason for this phenomenon.