Hot springs bubbling up even though there are no volcanoes? Experience the mysteries of the Earth up close at the Yuzawa Geopark [Akita Prefecture]

Yuzawa City in Akita Prefecture is famous for its local industries such as Inaniwa udon noodles and sake, which are located near Yamagata and Miyagi Prefectures. However, as its name "Yuzawa" (meaning "hot spring") suggests, it is also a hot spring paradise with many hot springs such as Koyasu Gorge Onsen, Oyu Onsen, and Akinomiya Onsenkyo.

Yuzawa City is located in the inland part of Akita Prefecture. Generally, the presence of hot springs in such a location often indicates the presence of a nearby volcano, but looking at the entire city, there are no signs of an active volcano at present

In neighboring Miyagi Prefecture stands Mount Kurikoma, an active volcano, but it's a bit too far to generate hot springs in Yuzawa City. So why are there so many hot springs in Yuzawa City?

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The remains of a volcano from several decades ago provide hot springs

Tracing the history of the Yuzawa City area reveals that extremely intense volcanic activity occurred there millions to hundreds of thousands of years ago. Over a long period of time, due to tectonic shifts and other factors, that volcano sank deep underground and disappeared from the surface

However, the remnants of that volcano deep underground have only disappeared from the surface; they continue to be active beneath the surface

Kawarage Jigoku, a barren plateau that emits sulfur dioxide gas, Oyasukyo Daifunto, a geyser that spews high-temperature steam and hot water . These phenomena are evidence that the gas is being supplied from a volcano deep underground.

has been designated a "Yuzawa Geopark," a geopark that likens the Earth's activity to a large park

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The geothermal temperature beneath the foot of Mt. Takamatsu, which is not a volcano, is approximately 300°C

Mount Takamatsu (elevation 1315m), where "Kawarage Jigoku" is located, ceased erupting approximately 260,000 years ago, but it is said that magma remains beneath its surface

According to the Yuzawa Geopark blog, the geothermal temperature from the summit of Mt. Takamatsu to the surrounding area at an altitude of minus 500m is 300℃ near the summit, 250℃ at Kawarage Jigoku, about 2km from the summit, 200℃ near the Uenodai Geothermal Power Plant a little further down, and around 100℃ even further down around Akinomiya Onsenkyo. Near the Uenodai Geothermal Power Plant, the temperature is about 100℃ close to the surface

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Kawarage Jigoku, where no plants grow, is one of Japan's three most sacred places

Kawarage Jigoku is a representative tourist spot in Yuzawa City, one of Japan's leading geothermal areas. High-temperature steam containing hydrogen sulfide, heated by the heat of magma lying deep beneath Mount Takamatsu, erupts to the surface, creating a desolate white plateau where no plants grow and even animals and insects cannot approach.

In 807, the monk Gessō visited this area and established Reitsūzan Zentōji Temple (now relocated to Hirosawaji Temple in Inaniwa, Yuzawa Town), and it became a sacred site and an object of worship

From ancient times to the Middle Ages, along with Mount Osore (Aomori Prefecture) and Mount Tateyama (Toyama Prefecture), it was one of the three major sacred sites and was visited by many ascetic monks and pilgrims.

During the Ashikaga period, Zen'yuji Temple was relocated to a slightly distant foothill, and in the Edo period, a sulfur mining site was established, leading to fewer Shugendo practitioners visiting "Kawarage Jigoku" (Kawarage Hell)

Currently, it has become a tourist destination with walking trails, making it a valuable place where you can see Earth's activity up close

Kawarage Jigoku (Kawarage Hell) is a hot spring resort where toxic gases containing hydrogen sulfide and other substances, as well as boiling water at nearly 100°C, are spewed out, so caution is advised when exploring the area. Also, from early November to early May, the road leading to the site is closed due to snow, making it impossible to visit during that time

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The Kawarage Oyu Falls, where hot spring water flows down, has a natural open-air bath at its base

Kawagege Ooyu Falls is a waterfall where high-temperature hot spring water flowing from "Kawagege Jigoku" mixes with stream water and cascades down from a height of 20 meters. serves as a natural open-air bath

The temperature is just right during the summer. Swimsuits are required, and a simple changing room is provided. It's about a 15-minute walk from the parking lot and about a 35-minute walk from the Kawarage Jigoku parking lot

Bathing is free, but the facility is closed from early November to early May. Even in mid-summer, the water can be cold if it rains or during seasons other than summer, so please be aware of this

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Mud Hot Springs, known for its high-temperature hot springs containing sulfur

Doroyu Onsen is a hot spring that gushes forth on the slopes of Mt. Takamatsu, about 2km from "Kawarage Jigoku" (Kawarage Hell). The hot spring is said to have been discovered about 1200 years ago, and milky white, high-temperature sulfur spring water gushes out. There are two hot spring facilities, but the area around the facilities is off-limits because the geothermal temperature reaches 100°C, and hydrogen sulfide-containing gas and hot water are spewing out.

"Doroyu Onsen Okuyama Ryokan" is a long-established inn that has been in business since the Edo period. The hot springs draw on sulfur springs (Tengu no Yu), as well as simple hot springs (Shinyu) that well up in the surrounding area, and sulfur springs (hydrogen sulfide type/Kawa no Yu) that have different components than Doroyu, so you can spend a relaxing time enjoying the hot springs. Day trips are also possible

The other, Ogura Ryokan, is a hot spring facility that only accepts day-trip bathers. The hot spring water is acidic. It is closed during the winter (mid-November to April)

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The "Oyasu Gorge Great Geyser" is a hot spring where boiling water erupts from a crack in the rock

Oyasukyo Gorge is a V-shaped canyon carved out by the erosion of the Minase River, and it stretches for 8 km.

The Oyasukyo Great Geyser where high-temperature hot spring water erupts with a roar from a crack in the riverbed , is evidence of the Earth's active volcanic activity. The view from the walking path and from 60 meters up on the bridge is spectacular. There is a footbath at the Minase Tourist and Local Products Center, which has a parking lot.

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Koyasukyo Onsen, which opened during the Edo period, is the largest hot spring in Yuzawa

Along the Minase River are Oyasukyo Onsen and Oyu Onsen

Oyasukyo Onsen is a historic hot spring that was discovered during the Edo period, with 11 hot spring inns lined up along the Minase River near the Oyasukyo Great Fountain. The hot springs are alkaline simple hot springs and boast an abundant supply of water

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Oyu Onsen, a hidden gem gushing forth deep within the Koyasu Gorge hot springs

Oyu Onsen is a hot spring located at the uppermost reaches of the Minase River, and its water quality is alkaline sulfur spring water. There are two hot spring facilities. This is a hot spring inn where you can fully enjoy the great outdoors of Oku-Oyasu

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Akinomiya Onsenkyo is a hot spring resort area where six inns each own a different hot spring source

"Akinomiya Onsenkyo" is the collective name for six hot springs scattered around the western foot of Mt. Takamatsu. Each of the six hot springs has its own inn, and each has its own source with a different spring quality. There are also many other unknown, unused hot springs around Mt. Takamatsu, which is where the name "Yuzawa" comes from

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Uenodai Geothermal Power Plant: Enough Power to Power the Entire City of Yuzawa

The Kaminodai Geothermal Power Plant is a geothermal power plant that generates electricity using high-temperature steam accumulated underground on Mount Takamatsu. Its power output is 28,800 kW (as of 2022), equivalent to the electricity consumption of the entire city of Yuzawa

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Yuzawa Geopark: A place to learn about and play with the Earth

Yuzawa Geopark is home to several caldera remains formed by eruptions between 3 and 7 million years ago. In addition, there are many traces of times when the Earth was more active, such as outcrops where older strata are exposed, creating a spectacular landscape. The Earth is not only home to hot springs, but also to pure fresh water that enriches people's lives and produces many local specialties, such as Inaniwa udon noodles and sake, such as Ranman and Ryoseki. Why not spend your holidays at Yuzawa Geopark, where you can witness the Earth's dynamic activity with your own eyes?

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