Mount Onnebetsu - Mount Onnebetsu

...The eastern coast faces Kunashiri Island across the Nemuro Strait. The Shiretoko mountain range, which includes Mount Unabetsu (1,419m), Mount Onnebetsu (1,331m), the highest peak Rausu (1,661m), Mount Io (1,563m), and Mount Shiretoko (1,254m), which erupted in the Quaternary period, runs vertically through the area and forms the watershed between the eastern and western coasts of the peninsula. Mount Io is an active volcano with a horseshoe-shaped explosion crater (approximately 1.2 km in diameter) that opens to the north at its peak. It has erupted four times since the Meiji period, and in the eruptions in 1889 and 1936, it spilled large amounts of molten sulfur onto the northern foothills.

*Some of the terminology that refers to "Onnebetsu-dake" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…東岸は根室海峡を隔てて国後（くなしり）島に相対する。新第三紀の堆積岩，火山角レキ岩，凝灰岩などを基盤とし，第四紀に噴出した海別（うなべつ）岳(1419m)，遠音別（おんねべつ）岳(1331m)，最高峰の羅臼岳(1661m)，硫黄山(1563m)，知床岳(1254m)などの知床連山と呼ばれる山脈が縦走し，半島の東岸と西岸の分水界をなす。硫黄山は頂部に北側に開いた馬蹄形の爆裂火口(径約1.2km)をもつ活火山で，明治期以降にも4回の噴火を繰り返し，1889年，1936年の噴火の際には北麓に多量の溶融硫黄を流出させた。…

※「遠音別岳」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報