HOKKAIDO, Dec 04, 2025 (News On Japan) - A volcano education center at the base of Showa-Shinzan is facing an existential threat as aging facilities and deteriorating materials put decades of invaluable records at risk.
A plume of white steam continues to rise from the side of Showa-Shinzan, and at its foot stands a bronze statue of Masao Mimatsu, the man who devoted himself to observing the volcanic dome formed during the 1943 eruption of Mount Usu.
Mimatsu was the local postmaster when Showa-Shinzan emerged amid wartime shortages, a period when neither cameras nor proper observation equipment could be obtained. Captivated by the creation of a new mountain, he continued to document its formation in precise sketches and notes throughout the final years of the Pacific War. His vast collection of drawings, diagrams, and journals was later preserved by Saburō Mimatsu, the husband of Mimatsu’s granddaughter.
Kagaya Nire, deputy director of the Toya-Usu Geopark Promotion Council, explains that Saburō dedicated himself to safeguarding this geological heritage and using it for educational purposes. Today, however, the museum established to preserve these materials—and the legacy they represent—is in crisis.
The Mimatsu Masao Memorial Hall, located at the foot of Showa-Shinzan, houses roughly 4,000 items, including drawings capturing the violence of the eruptions and detailed diaries tracking the mountain’s transformation. Among the most important documents are the “Mimatsu Diagrams,” a series of meticulous records showing step by step how Showa-Shinzan rose from the earth.
For nearly two years, Mimatsu conducted fixed-point observations of the newborn mountain, recording the full process of its uplift after the eruption. “It was a time when you couldn’t easily get cameras or film, so he captured everything in drawings,” said Kawanami Emiko, head of the Toya-Usu Volcano Meister Network. A recording of Mimatsu’s own voice remains in the HBC archives, where he recalled the chaos of the wartime eruption and the daily uplift of about 30 cm amid violent activity.
Mount Usu typically erupts every 20 to 30 years. Mimatsu passed away in 1977, coincidentally the same year the volcano erupted again. Saburō Mimatsu then carried on the work, building the memorial hall in 1988 and devoting himself to volcanic disaster education.
In March 2000, Mount Usu erupted once more. While hot springs districts and surrounding highways suffered heavy damage, early detection of warning signs made it possible for about 16,000 residents to evacuate before the eruption, and no lives were lost. The efforts of Masao and Saburō Mimatsu are widely regarded as part of the foundation for this “miracle.”
“Mount Usu erupts repeatedly, so how we use the story of Showa-Shinzan’s birth for the next eruption is crucial,” Saburō said in 2014. He spent decades teaching children and local residents about living alongside volcanoes, sharing practical knowledge rooted in the Mimatsu family’s long record of observation. In July this year, he passed away at his home in Sōbetsu Town while gazing at Showa-Shinzan through the window.
“Learn about volcanoes properly, fear them properly, and evacuate properly—this is what Saburō Mimatsu taught as part of regional education,” Kagaya said on the 21st.
Yet the memorial hall is facing severe challenges. “This is the Mimatsu Masao Memorial Hall,” reporter Baba Yurika explained from the site. “It has long served as a hub for volcanic disaster education, but with the building aging and valuable materials deteriorating, it now confronts a major crisis.”
Built about 40 years ago, the facility lacks air conditioning and other environmental controls. Most of the collection consists of paper, which is now suffering damage due to rising summer temperatures and increasing humidity.
“Climate patterns are changing, humidity is rising, and these items were protected with great care by Saburō,” Kawanami said. “If they truly mattered to him, then we must take proper responsibility and protect them even more.”
Source: HBCニュース 北海道放送
