Shikotsu-Tōya National Park

Listen first. Somewhere close by, steam is hissing out of the ground. There is a faint smell of sulphur, like struck matches, mixed with the cold green scent of birch and pine. Underfoot, the soil is dark and gritty. That grit is volcanic ash and pumice. Almost everything you see in this park, from the lakes to the mountains to the hot water in the baths, was made by fire from deep below the earth.

Welcome to Shikotsu-Tōya National Park, in the southwest of Hokkaido, Japan's northern island. The park was designated in 1949. It is not one single place. It is a scattered collection of volcanic landscapes, spread across a wide area between Sapporo and the Pacific coast. Two great lakes give the park its name. Around them sit active volcanoes, steaming valleys, and some of the best known hot spring towns in northern Japan.

Start with Lake Shikotsu, the northern anchor of the park. It fills a caldera — a huge hollow left behind when a volcano collapses after a massive eruption. The name is often traced to the Ainu language, the language of Hokkaido's Indigenous people, where it is understood to describe a large depression or hollow. That fits. The lake is more than 350 metres deep, which makes it the second deepest lake in Japan. Only Lake Tazawa, on the main island of Honshu, goes deeper.

Here is the first surprise. Because the lake holds so much water, it stores summer heat for a long time. Even in Hokkaido's hard winters, with snow piled high on the shore, Lake Shikotsu usually does not freeze over. It is often described as the northernmost lake in Japan that stays largely ice free. The water is also very clear. On a calm day, people talk about Shikotsu blue — a deep, cold colour that turns almost turquoise in the shallows near the shore.

Look around the rim of the lake and you will see a ring of volcanoes. Mount Tarumae, to the south, is still active. Its summit holds a rounded lava dome that pushed up out of the crater, like a stone cork in a bottle. Mount Eniwa rises to the north. Its slopes were used for downhill skiing events during the Sapporo Winter Olympics in 1972. These mountains are not scenery from the distant past. They are part of a living system.

Now travel south, toward Lake Tōya. This is another caldera lake, and its shape is close to a circle. In the centre sits a group of forested islands, known together as Nakajima, which simply means the middle island. From the shore, the islands look dark and soft against the water. Like Shikotsu, Lake Tōya does not usually freeze in winter. During the warmer months, small fireworks shows over the lake have become an evening tradition for visitors staying along the shore.

On the southern edge of Lake Tōya stands Mount Usu, and this is where the park's story becomes truly dramatic. Mount Usu is one of the most active volcanoes in Japan. It has erupted several times in the last century alone. Each eruption has reshaped the land around it — raising hills, cracking roads, and moving the ground beneath farms and houses. People here live with the volcano, not simply beside it.

The second surprise is a mountain that did not exist a lifetime ago. Between 1943 and 1945, during the Second World War, the ground near Mount Usu began to bulge upward. A flat area of farmland rose, slowly at first, then faster. In about two years, a new lava dome stood where crops once grew. It was named Shōwa-shinzan, the new mountain of the Shōwa era. Today its reddish, bare summit still steams in places.

The new mountain has a remarkable human story. A local postmaster, Masao Mimatsu, recorded its growth carefully, day after day, during wartime when official information was restricted. His simple measurements became a valuable scientific record, now known as the Mimatsu diagram. He later bought the land himself, so that the young mountain would be protected. Shōwa-shinzan remains privately owned, which is very unusual for a natural landmark of this size.

Mount Usu erupted again in 2000. This time, scientists had been watching closely, and they warned of the danger in time. Thousands of residents were evacuated before the eruption began. Buildings were damaged and roads were broken, but no lives were lost. Some of the ruined structures have been left in place on purpose. Walking trails now lead past them, so that visitors can see what a volcano does to a town. The wider area is recognised as the Tōya-Usu UNESCO Global Geopark.

The heat that builds mountains also fills the baths. Noboribetsu, on the eastern side of the park, is one of Japan's best known hot spring towns. Just above the town lies Jigokudani, which means Hell Valley. It is a bowl of pale, crumbling rock, streaked with yellow and orange, where steam rises from vents and pools bubble grey. Wooden walkways carry visitors through it. The smell is strong, and the ground is warm. Not far away, the park also reaches Jōzankei, a hot spring town set in a river gorge close to Sapporo.

Then there is Mount Yōtei, the tall, almost perfect cone that rises over the western part of the park. Because of its symmetrical shape, many people call it Ezo Fuji. Ezo is an old name for Hokkaido, so the nickname means the Mount Fuji of the north. In early winter, snow lines its slopes like white ribs. In spring, melted snow soaks into the volcano and returns as cold, clear spring water at its base.

This park also hosted world leaders. In 2008, the G8 summit was held at a hotel on a ridge above Lake Tōya. Political leaders from the world's largest economies met here, surrounded by the same volcanoes and forests you see today. It is a reminder that this quiet corner of Hokkaido is not remote from the wider world. It simply moves at a different pace, set by the seasons and by the ground itself.

So take a moment, wherever you are standing now. Notice the colour of the water, or the steam drifting from a hillside, or the dark ash in the soil at your feet. All of it is part of one long, slow process that is still going on. As you walk on, listen for the wind in the birches and the hiss of a vent. The land here is still being made, quietly, right in front of you.