Slochter

Japanese: Slochteren

...The marine clay and peat areas inside the dikes have been reclaimed and turned into fertile farmland. Near Slochteren in eastern Groningen, an air-tight salt layer formed on top of the peat, which has resulted in huge reserves of natural gas. In 1932, the Zuiderzee's closing dike (29.8 km) was built, and a motorway on the dike connected the provinces of North Holland and Friesland. The Zuiderzee was transformed into four large polders, including the Nooroostpolder (reclaimed land), and the freshwater IJsselmeer (area 1,200 km2).

From the Groningen gas field

…A gas field located about 150 km northeast of Amsterdam, on the coast of the North Sea in the Netherlands. It is also called the Slochteren gas field. It was discovered in 1959 and marked the beginning of the discovery of many gas fields in the vast area stretching from northwestern Europe to the southern North Sea.

*Some of the terminology explanations that mention "Slochteren" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…堤防の内側の海成粘土と泥炭の地域は干拓され肥沃な農地に変えられた。フローニンゲン東部のスロホテレンSlochteren付近には，泥炭層の上に空気を通さない岩塩層が形成されたため膨大な量の天然ガスが埋蔵されている。1932年ゾイデル海の締切り堤防(29.8km)が築かれ，堤防上の自動車道路で北ホラント州とフリースラント州は結ばれ，ゾイデル海は北東ポルダー(干拓地)をはじめとする四つの大ポルダーと淡水のアイセル湖(面積1200km2)に変貌した。…