Hanawa basin - Hanawabonchi

A graben basin in the upper reaches of the Yoneshiro River in northeastern Akita Prefecture. It is also called the Kazuno Basin. It borders the Ou Mountains to the east and the Takamori Mountains to the west. The floor of the basin is made up of four terraces, and the alluvial plains of the Yoneshiro River and Kosaka River cut through them. The sediments that make up the terraces are mainly pumiceous volcanic ash from the Towada Volcano. They are used as farmland and apple orchards. The alluvial plains are distributed in a narrow strip along the current rivers, and have developed widely as alluvial fans from the center to the east of the basin, which have been turned into rice paddies. The water system is biased to the west, with the main stream of the Yoneshiro River flowing north along the western edge of the basin, merging with the Kosaka River near Nishikigi, and forming a leading channel that connects to the Odate Basin to the west. The center of the basin is Kazuno City, which belonged to the Morioka Domain during the Edo period, and there are also connections to Iwate Prefecture through immigrant settlers and intermarriage.

[Reijiro Miyazaki]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

秋田県北東部、米代川(よねしろがわ)の上流部にある地溝盆地。鹿角盆地(かづのぼんち)ともいう。東部は奥羽山脈、西部は高森山地と接する。盆地床は四段の段丘面と、これを切る米代川および小坂川の沖積地からなる。段丘を構成する堆積(たいせき)物は十和田火山(とわだかざん)の軽石質火山灰などを主とする。畑地やリンゴ園として利用される。沖積地は現河川沿いに狭長に分布するほか、盆地中央部から東部にかけて扇状地として広く発達し、水田化されている。水系は西に偏っており、米代川本流が盆地西縁を北流し、小坂川と錦木(にしきぎ)付近で合流し、先行性の流路となって西方の大館(おおだて)盆地に通ずる。盆地の中心は鹿角市で、江戸時代は盛岡藩に属し、移住開拓者や通婚も岩手県との関係がみられる。

［宮崎禮次郎］

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