Mt. Yakeyama
Mt. Yakeyama, also known as Cha-usu Dake, is an active volcano with a height of 2,400 meters, straddling Myoko City and Itoigawa City in Niigata Prefecture, marking the northernmost point of the Myoko Volcanic Group. The foundation of the mountain is a Tertiary stratum at 2,000 meters above sea level, characterized by andesitic lava. The summit features a lava dome, with lava flows and pyroclastic flows primarily descending to the north. Classified as a small stratovolcano, its current form was shaped by an eruption that began around 3,000 years ago and culminated in a significant eruption in 1361. To distinguish it from another Yakeyama in Akita Prefecture, it is sometimes referred to as Niigata Yakeyama.
At the peak lies a central crater known as "O-hachi," with a smaller explosive vent to the west. The mountainside is dotted with numerous sulfur vents, fumaroles, and fissures, some of which remain active today.
Yakeyama has continued to experience phreatic explosions in recent years. In 1949, an eruption caused ashfall and mudflows. Between 1962 and 1963, small eruptions, ashfall, and abnormal acoustic phenomena were recorded. An eruption on July 28, 1974, led to ashfall in the Joetsu region, tragically claiming the life of a student conducting research. Since then, fumarolic activity has intensified periodically, with small eruptive events still occurring.
For hikers, a route exists that starts from the Sasakura Onsen in Hayakawa Valley, follows the construction road along the Hiuchiyama River to Amana Plateau, passes through Sai-no-Kawara, and continues over Bouboudaki and Tomaridake rocks to the summit (approximate duration: 6 hours). Some trails traverse from Mt. Hiuchi to Mt. Amakazari and from Sasagamine Pasture following the Sadagawa River. There may be restrictions placed around the summit area, so climbers must check the latest information before setting out.
*Before heading out on a hike, make sure to stay updated with the latest information on trails and other important details.