{"id":337,"date":"2025-08-28T10:44:22","date_gmt":"2025-08-28T01:44:22","guid":{"rendered":"https:\/\/geo-itoigawa.com\/en\/?page_id=337"},"modified":"2026-01-30T13:42:00","modified_gmt":"2026-01-30T04:42:00","slug":"area20","status":"publish","type":"page","link":"https:\/\/geo-itoigawa.com\/en\/igp\/area\/area20\/","title":{"rendered":"20. Yakeyama"},"content":{"rendered":"\n\n

Yakeyama Area<\/h1>\n

Hot springs and Disaster Prevention beneath an Active Volcano<\/p>\n\t

Mt. Yakeyama is a young active volcano<\/b> at the northernmost tip of Fossa Magna<\/b> born only some 3,000 years ago<\/b>. The body of the mountain is a lava dome formed in 1361<\/b>, during Japan’s Muromachi period. It is still astir with fumarolic activity. Like Mt. Fugendake at Unzen in Kyushu, Mt. Yakeyama has erupted several times in the past, sending pyroclastic flow and ash into the valley below. According to geological surveys, the mountain has particularly violent eruptions about every 400 years<\/b>, with eruptions during the Heian<\/b> and Muromachi<\/b> periods sending pyroclastic flow<\/b> down over 20km<\/b> to the coastline.<\/p>\n

Nakagawara Terrace, formed as a result of pyroclastic flow<\/b> during the Heian period<\/b> (1200 years agoth) eruption, proved unsuitable for rice cultivation-the drainage was too good. During the Edo period, this area underwent extensive development to improve water retention and is now covered with beautiful and productive rice fields. Here within the verdant Joshin’etsu Kogen National Park<\/b> you can see pyroclastic deposits, hardened lava flows, the remnants of beech forests buried by volcanic eruptions, and the mudstone that forms the foundation of Mt. Yakeyama. This mudstone has traditionally been used to make the inkstones used in Japanese calligraphy. In addition, you can see many dikes and other facilities built to protect against erosion, avalanches, and pyroclastic flow. With the threat of catastrophic eruption and the dangers of steam vents, life under a volcano is certainly dangerous, but not without its blessings-before leaving this geosite, be sure to relax in one of the hot springs<\/b> here, the volcano’s gifts to us all.<\/p>\nWorning\u3000
About Climbing Mt. Yakeyama<\/u><\/strong>
\nGate #1 between Sasakura Hot Springs and the Mt. Yakeyama trailhead is only open to vehicle traffic on Saturdays, Sundays & Public Holidays. Walking is permitted even on weekdays. Gate #2 is closed to vehicle traffic at all times.\n

Mt. Yakeyama has almost no fountainheads or other sources of water and the trail is rugged and lacks many safety provisions. Ascending Mt. Yakeyama is for experienced climbers only. Sudden volcanic activity is possible at any time, so special caution is recommended when visiting Mt. Yakeyama.<\/p>\n\t\"Yakeyama\n \n \"Mt.\n \"Control\n \"Kamihayakawa\n \"Buried\n \"Mt.\n \"Hot\n \"Formed\n \"Terrace\n <\/map>\n\t

1Mt. Yakeyama<\/h2>\n\t\t\t\t\"\"\n\t

Mt. Yakeyama<\/p>\n\t\t\t\t\"\"\n\t

Alpine Flora: Gentian<\/p>\n\t\t\t\t\"\"\n\t

Alpine Flora: Wintergreen<\/p>\n\tYakeyama, or “the burning mountain,” is located on the border between the cities of Itoigawa and Myoko. Along with nearby Mt. Myoko and Mt. Hiuchi, these mountains make up the Kubiki Mountains. The summit is 2,400 m high, but only the top 400 m are volcanic in origin.
\nThere are no concrete records of any lava flow or pyroclastic flow since 1773, but other eruption events have been confirmed to the present day. On July 28th, 1974, Mt. Yakeyama saw its most recent major eruption, a steam-blast eruption which took the lives of three students from Chiba University who were studying plant life in the area. The mountain was closed to climbers after the eruption, but was reopened in late 2006.\n\t

2Control Dams<\/h2>\n\t\t\t\t\"\"\n\t

Hiuchiyamagawa River Control Dam #1<\/p>\n\t

To prepare for the possibility of another volcanic eruption, the Japan Meteorological Agency has installed seismometers and Niigata Prefecture has installed cameras throughout the area. Along the Hiuchiyamagawa and Yakeyamagawa Rivers, a number of control dams have also been built to temporarily stop or slow landslides and pyroclastic flow.<\/p>\n\t

3Carbonized Wood at Nakagawara Terrace<\/h2>\n\t\t\t\t\"\"\n\t

Carbonized Wood Encased in Volcanic Ash<\/p>\n\t

Carbonized wood occurs when trees are quickly converted to carbon by the intense heat of pyroclastic flow. During construction at the former Kamiyakawa Elementary School, a great amount of carbonized wood was discovered. This area, called Nakagawara Terrace, was formed from volcanic ash about 1000 years ago. During Japan’s Edo period era, this terrace was converted into rice fields that can be seen today.<\/p>\n\t

4Buried Beech Trees<\/h2>\n\t\t\t\t\"\"\n\t

Buried Beech Tree<\/p>\n\t

Beech trees in the valley below offer a glimpse into the history of Mt. Yakeyama. These trees, over 3000 years old, were buried when Mt. Yakeyama first erupted. Because of this, we know that this area was once a beech forest before Mt. Yakeyama was born.<\/p>\n\t

Nunakawa Inkstone<\/h2>\n\t\t\t\t\"\"\n\t

The mudstone deep in the valley was once known as Nukawa Suzuri and was highly valued for inkstones used in the practice of Japanese calligraphy. Fossils of fish and other marine life can sometimes be seen in this mudstone, evidence that the entire region was once at the bottom of the sea.<\/p>\n\t View Map\n