Naruko

Naruko is a volcanic mountain range near Osaki featuring a wide caldera with several lava domes scattered across the landscape. Geothermal features including hot springs and steam vents mark the slopes and valleys throughout the area.

This volcano formed through two major periods of pyroclastic activity thousands of years ago, followed by the gradual building of lava domes that shaped the terrain. The layers of volcanic rock visible today tell the story of this extended formation process.

The name Naruko comes from Japanese words meaning 'a place with a trembling voice', reflecting the volcanic nature of this landscape. Walking through the geothermal areas, visitors experience the connection between the name and the living geology beneath their feet.

The area offers multiple hiking trails suited to different experience levels and physical abilities. Weather conditions and seasons affect which paths are safely accessible, so checking current conditions before visiting helps plan your route.

At the center of the caldera sits a lake with extremely acidic water that reflects the intense geothermal activity still occurring today. The extreme acidity makes it one of Japan's most unusual natural water bodies.

Elevation above the sea: 470 m

GPS coordinates: 38.73359,140.72454

Latest update: December 12, 2025 09:02