Akita Plain - Akita Heiya

A plain stretching along the Sea of ​​Japan in the mid-western part of Akita Prefecture. It includes the Tenno sand dunes that extend from the Oga Peninsula in the north to the south, the Hachirogata polder, and alluvial plains created by the accumulation of materials transported by the Omono River. The coastal sand dunes on the left bank of the Omono River spillway were accumulated on top of Tertiary bedrock hills, and sand moved inland, causing damage until reforestation by Kurita Sadanojo during the feudal period. The downstream of the Omono River has undergone many changes in its course, and the old Omono River that flows into Tsuchizaki Port also changed course due to ground movements caused by earthquakes. This river frequently floods, and in 1938 (Showa 13) a spillway was constructed to cross the sand dunes and flow into the Sea of ​​Japan. The eastern part of Hachirogata is a plain created by the accumulation of materials transported by the Babame River. The Tenno Sand Dunes were formed by secondary deposition of materials transported from the Omono River along the coast, and the sand dune rows are divided into three. The area between Akita City, the center of the plain, and Funakawa in Oga City has seen remarkable urbanization. Rice is the main agricultural crop.

[Reijiro Miyazaki]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

秋田県中西部、日本海沿いに展開する平野。北の男鹿(おが)半島から南へ延びる天王(てんのう)砂丘、八郎潟(はちろうがた)干拓地、雄物川(おものがわ)の運搬物の堆積(たいせき)によってつくられた沖積地を含む。雄物川放水路左岸の海岸砂丘は、第三紀の基盤丘陵の上に堆積したもので、藩政期に栗田定之丞(くりたさだのじょう)によって植林が行われるまでは砂が内陸に移動して被害を与えた。雄物川下流は河道の変遷が多く、土崎港に流れ込んでいる旧雄物川も地震による地盤変動によって流路を変えたものである。この川はしばしば洪水をもたらし、1938年（昭和13）砂丘を横断し日本海に流れるように放水路の工事が行われた。八郎潟の東部は馬場目(ばばめ)川の運搬物が堆積してできた平野である。天王砂丘は雄物川からの運搬物が二次的に沿岸に堆積したもので、砂丘列は3条に分かれる。平野の中心地としての秋田市と男鹿市船川を結ぶ地域の都市化が著しい。農業は米作主体である。

［宮崎禮次郎］

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