Mt. Meakan and the Yunotaki Lava Flow
Mt. Meakan is a highly active volcano located at the southwestern end of the Akan-Shiretoko Volcanic Group. It was formed tens of thousands of years ago and is composed of 10 volcanic peaks. Repeated eruptions have changed the shape and location of its peaks, craters, and lava formations over thousands of years.
How the lava flow was formed
Mt. Meakan’s tallest peak, Pon-machineshiri (1,499 m), began erupting 7,000 years ago. Molten lava from the eruptions poured down the western and southern slopes of Mt. Meakan, forming the Yunotaki Lava Flow. The cooled, hardened lava contains various minerals, one of which is manganese.
A geothermal waterfall
The water cascading down Onneto Yunotaki Falls first fell as rain decades ago, seeping slowly into the volcanic rock on Mt. Meakan. As the geothermally heated water passes through the lava, manganese ions dissolve into it. The hot water springs from the top of Onneto Yunotaki Falls and runs down the end of the Yunotaki Lava Flow. The water temperature at the falls reaches as high as 43℃.
The peaks of Mt. Meakan
The Pon-machineshiri crater continues to emit plumes of volcanic steam that can be seen from the trail to the summit of Mt. Meakan and other vantage points in Akan-Mashu National Park. An observation deck on the western shore of Lake Onneto, about 3 kilometers from here, offers a panoramic view of Mt. Meakan’s volcanic peaks. The large asymmetrical peak to the north is Pon-machineshiri, and the cone-shaped peak to the south is Mt. Akanfuji. Both peaks are relatively new volcanoes formed atop the base of Mt. Meakan.
