[Miyagi Prefecture] Mt. Kurikoma Geopark learning from large-scale landslide disasters

Kurikomayama is a volcano with an altitude of 1,626m located on the border of Miyagi, Iwate, and Akita prefectures.In Iwate PrefectureMt. SugawaIt is also called (Sukawa Dake). It belongs to the Nasu volcanic belt, has erupted twice in recorded history (1744 and 1944), and is still an active volcano with active seismic activity. A small phreatic eruption in 1944 formed Lake Showa in the crater ruins halfway up the mountain.

Large-scale landslides occur due to Iwate-Miyagi Nairiku Earthquake

The Iwate-Miyagi Nairiku Earthquake in 2008 caused the most damage.The earthquake with a depth of 8 km and M7.2 occurred on June 14th with its epicenter approximately 10 km northeast of Mt. Kurikoma, with a maximum seismic intensity of 6+.This earthquake caused a large-scale landslide at the foot of Mt. Kurikoma on the Miyagi Prefecture side, resulting in a disaster that caused significant human damage.

During the Iwate-Miyagi Nairiku Earthquake, slope deformation was observed at more than 3,500 large and small locations on the fault that caused the earthquake.In particular, the landslide that occurred upstream of Aratosawa Dam was large-scale, with a length of 1,300 m, a maximum width of 900 m, and a cliff height of 150 m.The amount of soil that slid down (unstable sediment generation amount) was 67 million m3. The amount is equivalent to 54 Tokyo Domes.

The Ou Mountains, where Mt. Kurikoma is located, are the newest mountain ranges in Earth's history.

Numerous slope changes, including the Aratosawa landslide, are said to be caused by the formation of the Ou Mountains.The Ou Mountains are a mountain range that connects the watersheds of the Tohoku region (backbone mountains), and are the newest mountain ranges in the world.The ground that was on the ocean floor has risen, and various deposits accumulated from subsequent volcanic activity have piled up on top of the old ground, forming a mille-feuille-like stratum. The old solid ground and the new, unsolidified stratum on top of it. The ridgeline of Mt. Kurikoma is made up of geological formations that meet these conditions, and an avalanche-like landslide occurred due to a gigantic, short-cycle earthquake that shakes finely over a short period of time.

Many landslides, ranging from the large ones that occurred in Aratosawa to the small ones, have occurred in people's living areas, and recovery efforts are still continuing more than 15 years later.

The foot of Mt. Kurikoma is a valuable geopark where you can learn about the earth's activities.

Kurihara City, Miyagi Prefecture, which includes the area where the landslide occurred, has been certified as the Kurikoma Foothills Geopark. Geoparks are parks created by the earth. Not only do they provide dynamic natural playgrounds, but they also sometimes, like Mt. Kurikoma, challenge challenging battles to places where people lived peaceful lives without warning. One of the roles of geoparks is to research and learn to overcome these challenges. Activities have begun to utilize this landslide as an important teaching material for learning about the earth. The Aratosawa landslide area was selected as one of Japan's top 100 geological sites as the area where the Aratosawa dam collapsed.

The view from the top is spectacular. Mt. Kurikoma, which is relatively easy to climb

There are nine climbing routes to the summit of Mt. Kurikoma, which can be enjoyed by everyone from beginners to advanced climbers. The mountain trail is well-maintained, and there is a parking lot, washrooms, day-trip hot springs, and lodging facilities at the trailhead, so you can rest assured. It is possible to climb the mountain on a day trip, but camping is prohibited as it is within a national park.Also, please note that there are no mountain huts where you can stay overnight along the trail.

Mt. Kurikoma is still an active volcano, and there are areas near the summit that have active fumarole activity, so caution is required as it is a volcano that is constantly monitored by the Japan Meteorological Agency.

Climbing is restricted near Lake Showa, where a lot of toxic gas is spewing out.

As of July 2023, part of the Sugawa mountain trail on the north side is currently closed due to volcanic gases such as hydrogen sulfide gas spewing out near Lake Showa along the way. Traffic restrictions on the mountain trail from the foot of the mountain to Lake Showa will be lifted for a certain period of time in autumn. (Please inquire)

"Lake Showa" is a small lake that was formed during a small-scale eruption in 1944, and is a crater lake that was formed when water accumulated at the site of a crater.The water quality is strongly acidic and milky white.

The bright autumn leaves that cover the whole mountain are the biggest highlight of Mt. Kurikoma.

Kurikoma Mountainside is visited by many tourists as a famous spot for viewing autumn leaves.Around Iwakagami-daira, the trailhead that leads from the Mt. Kurikoma Geopark side to the summit, there is even a route bus that runs only in autumn to see the autumn leaves all the way to the summit. If you have a private car, you can only go as far as the Ikoinomura Kurikoma Ruins Parking Lot during the autumn leaves season. A shuttle bus will take you from [Ikoinomura Kurikoma Site Parking Lot] to [Iwakagami-daira Parking Lot].

The mountain is located at an altitude of 1,113m from the trailhead [Iwakakamidaira], and there are two routes to the summit. The central route is the shortest of the mountain trails, at 2.9km to the summit, and is well-maintained with a gentle slope, making it perfect for beginners. There are almost no dangerous spots, and you can leisurely walk back and forth within 3 hours. There is the Kurikoma Rest House in Iwakagami-daira, which has a store, restaurant, and toilets, and is a sturdy reinforced concrete building that can be used as a shelter.

INFORMATON

• Facility name: Iwakagamidaira trailhead/Kurikoma rest house
• Location: Koei Higashi, Kurikoma Numakura, Kurihara City, Miyagi Prefecture
• Phone number: 0228-43-4100
• Business hours: 9:00-17:00
• access:
• Railway/Approximately 1 hour by car from Kurikoma Kogen Station on the Tohoku Shinkansen
• Car: 50 minutes from Tohoku Expressway Kananari Wakayanagi IC
• *During the autumn period (early to late October), the route bus "Kurikomayama Momiji" runs once a day from Kurikoma Kogen Station on Saturdays, Sundays, and public holidays (operation periods and times can be found on the Miyako Bus homepage)
• URL: Miyako Bus (Miyagi Kotsu)
• URL: Kurikoma Rest House

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World valley primeval flower garden where daylilies turn yellow

The World Yachi Primeval Flower Garden is a long, narrow wetland that spreads out on a plateau at an altitude of around 700 meters, and has an area of ​​about 14 hectares, which is about three times the size of Tokyo Dome.Sekai Yachi means "wide wetland" and consists of eight wetlands of various sizes in four groups spread out in three stages: upper, middle, and lower.

At the World Yachi Primeval Flower Garden, a variety of wetland flowers compete in bloom, from the skunk cabbage in May to the Ezo oyamarindo in September. The large clumps of day lilies that bloom in late June are especially spectacular, turning the entire wetland orange.

You can reach the wetland by walking for about 15 minutes from the private parking lot, and it has become popular as a wetland that anyone can visit.

INFORMATON

• Facility name: World Valley Primeval Flower Garden
• Location: Kurihara City, Miyagi Prefecture, Kurikoma Numakura Koueinan, Kurihara City, Miyagi Prefecture
• Freedom to stroll
• access:
• Railway: Approximately 1 hour and 10 minutes by car from Kurikoma Kogen Station on the Tohoku Shinkansen
• Car: Approximately 1 hour from Wakayagi Kananari IC on the Tohoku Expressway

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Hosokura Mine, where minerals were produced by volcanic activity on Mt. Kurikoma

The Hosokura Mine is a mine that was discovered at the foot of Mt. Kurikoma approximately 1,100 years ago and continued to be mined until 1987, producing silver and lead.During the Edo period, the Date clan put effort into mining, and mining continued with repeated ups and downs until 1987 (Showa 62). It was the war that transformed the Hosokura Mine into one of Japan's leading mines. In particular, World War I, which broke out in 1915 (Taisho 4), increased military demand for lead and zinc. That was until World War II, after which the mine was forced to close due to a decline in demand for lead and other materials.

The ore deposits at the Hosokura Mine are called "hydrothermal deposits," and the volcanic activity of Mt. Kurikoma plays an important role.Hot water warmed by magma deep underground rises to the surface while taking in various metal ions from rocks along its path. Due to environmental changes such as pressure and chemical reactions, the ions crystallize and precipitate in cracks in rocks. Minerals accumulated in the cracks are veins, and they contain many useful metallic minerals such as gold, silver, copper, lead, zinc, and tin. About this vein “Hydrothermal deposit”The ore deposits of the Hosokura Mine are exactly this type of "hydrothermal ore deposit."

After the Hosokura Mine closed in 1990, you can learn about the history of the Hosokura Mine and experience an underground exploration trip using the old mine shaft."Hosokura Mine Park"was reborn as. [Adventure Thorn] is used as a place for learning, as well as exhibits on the history of the Hosokura Mine and working scenes, as well as exhibits such as a gold panning experience and an exhibit that imagines the mine shaft as a space in which the universe was created. [Slider Park] is a thrilling slide with a gondola ride uphill and a 555m long slide downhill. From the observation deck, you can enjoy a panoramic view of the foothills of Mt. Kurikoma.

INFORMATON

• Facility name: Hosokura Mine Park
• Location: 2-3 Yanagisawa, Nango Uguisawa, Kurihara City, Miyagi Prefecture
• Phone number: 0228-55-3215
• business hours:
• March-November/9:30-17:00
• December-February/9:30-16:00
• Closed: Tuesdays (the next day if it is a holiday), New Year holidays
• *Open without holidays during Golden Week and summer vacation
• Admission fee:
• Sightseeing mine tunnel viewing/adults 500 yen, junior high and high school students 400 yen, elementary school students 300 yen
• Gold panning experience/adults, junior high and high school students 500 yen, elementary school students 400 yen
• access:
• Railway/About 40 minutes by car from Kurikoma Kogen Station on the Tohoku Shinkansen
• Car: Approximately 35 minutes from Tohoku Expressway Tsukidate IC, approximately 30 minutes from Wakayanagi Kananari IC
• URL: Hosokura Mine Park

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