玄武洞ミュージアム

Genbudo Museum is a geological museum in Toyooka City, Hyogo Prefecture, focused on the basalt rock formations of the Genbudo Caves area. The site achieved scientific prominence when Japanese geophysicist Motonori Matuyama conducted research here in 1929 that led to his discovery of geomagnetic reversal, proving that Earth's magnetic poles have flipped throughout history. This finding became crucial evidence for plate tectonics theory. The basalt formations studied by Matuyama formed approximately 1.6 million years ago when volcanic lava cooled and created distinctive hexagonal columnar structures through a process called columnar jointing.

The museum explains the geological processes that created the area's rock formations and the significance of Matuyama's research. The site encompasses five caves named Genbudo, Seiryudo, Byakkodo, Suzakudo, and Kokuryudo, each displaying different patterns of columnar basalt formed by varying lava cooling conditions. These formations are designated a National Natural Monument and a Geological Site of Japan due to their scientific importance and rarity. The basalt cliffs rise along the Maruyama River, creating a landscape where geological features combine with natural scenic beauty.

The museum features exhibits on geomagnetic reversal, volcanic processes, and regional geology through interactive displays and educational materials. After visiting the museum, guests can walk to the actual cave sites via riverside paths to observe the columnar basalt formations directly. Viewing platforms and trails provide access to the rock faces, with signage explaining formation details. The parkland surrounding the sites offers walking routes and rest areas overlooking the river. The geometric patterns of the basalt columns, particularly when reflected in the water, provide photographic interest alongside educational value.

Genbudo Museum is approximately 15 minutes by car from JR Toyooka Station, accessible via the JR San'in Main Line. Public buses run from Toyooka Station to the museum in about 20 minutes. Taxis and rental cars are alternative transport options from the station. The location in northern Hyogo Prefecture places it within the Kinosaki region, an area known for hot springs and coastal attractions. Museum admission costs 300 yen for adults, while the outdoor cave sites and parkland are free to access.