Devil's Washboard - Devil's Washboard

Japanese: 鬼の洗濯板 - おにのせんたくいた

…The alternating layers of sandstone and mudstone from the Miyazaki Group, which belongs to the Neogene Period, were eroded to form a marine platform, on which sand and shells were deposited to form an island. The sandstone is resistant to erosion by ocean waves and remains, but the mudstone is weak, so it has been indented, forming an uneven, wavy topography. It was given the name "Devil's Washboard" and was designated a natural monument in 1934. It is connected to the mainland by Yayoi Bridge, but at low tide the wavy topography appears all around and connects to the mainland, creating a landscape representative of the Nichinan Coast. …

From [Kesta]

...Therefore, the process of cuesta formation varies depending on the combination of these factors. For example, the "Devil's Washboard" on the wave-cut terrace of Aoshima, Miyazaki Prefecture, is a tiny cuesta that reflects the difference in mechanical strength and weathering rate between the sandstone and mudstone layers, while on the wave-cut terrace of the southern Miura Peninsula, tuff layers with relatively low mechanical strength form ridges, and marsh rock layers with high mechanical strength but with severe dry and wet weathering form valleys. In the central and western parts of the Boso Peninsula, cuestas that reflect mechanical strength and permeability develop.

From Nichinan Coast

...It is about 120 km from Aoshima in Miyazaki City to Kushima City in the south. From Aoshima in the north to Aburatsu in Nichinan City, the Neogene Udo Mountains run close to the sea, and thin alternating layers of sandstone and mudstone have been eroded by ocean waves to form a beautiful striped sea-cut platform called the Devil's Washboard. Small bays and capes can also be seen along the coastline.

*Some of the terminology that refers to "Oni no Sentakuita" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…新第三紀に属する宮崎層群の砂岩と泥岩の互層が浸食されて海食台をなし，その上に砂や貝殻が堆積して島を形成したものである。砂岩は海波の浸食に強いので残り，泥岩は弱いためにくぼみ，凸凹をした波状地形をなして，〈鬼の洗濯板〉と呼ばれ，1934年に天然記念物に指定された。弥生橋で陸と結ばれるが，干潮時には波状地形が周囲一面に現れて陸続きとなり，日南海岸を代表する景観をなす。…

【ケスタ】より

…したがって，ケスタの形成過程はこれら諸要因の組合せによって多様である。たとえば宮崎県青島の波食棚上の〈鬼の洗濯板〉は砂岩層と泥岩層の力学的強度と風化速度の差異を反映した微小なケスタだが，三浦半島南部の波食棚上では力学的強度の相対的に小さな凝灰岩層が尾根，力学的強度は大きいが乾湿風化の著しい沼岩層が谷となる。房総半島の中西部では力学的強度と透水性を反映したケスタが発達する。…