Yakehashiri Lava Flow was added to Your Favorites!
Towada-Hachimantai NP, Iwate
Claim this place to tell your story your way.
Historical records place Yakehashiri’s eruption at midnight on January 21, 1732; lava flowed for 7–10 days. Frequent volcanic quakes sent nearby residents fleeing, though no human or property damage was recorded.
An older national cultural-property entry dates Yakehashiri to 1719. In 1998, a volcanologist reexamined Edo-period records and linked a report of lava from Iwate’s northeastern foothills to the 1732 eruption instead.
Yakehashiri began on Iwate’s northeastern flank: lava escaped through several fissures 920–1,200 meters up, then traveled about 3 kilometers and spread nearly 1 kilometer wide.
Almost 300 years later, Yakehashiri is still largely treeless. Mosses and lichens colonize much of the rock, while higher plants—including pine—take hold only in scattered cracks, making the slow return of vegetation visible.
In his 1923 poem “Lava Flow,” Miyazawa Kenji imagined the dry moss as bread, ate an apple, and saw the distant Kitakami Mountains as the blue stripes of a farmer’s shirt. A monument to the poem stands beside the flow.
Among the angular blocks are rare, rounded “lava balls.” A Hachimantai City heritage guide says they may have formed when fragments of solidified lava rolled along inside the still-moving flow.
Some of Yakehashiri’s wavy, rope-like ridges are called “tiger forms” (tora-gata) in the official cultural-property description. Look closely: mosses and lichens cling to the ridges and their folds.
Higher up, near the remains of Yakehashiri’s first fumarole at about 1,220 meters, gravel hosts one of Japan’s largest komakusa habitats. Its delicate peach-colored flowers bloom in early summer.
The lava surface can reach 40°C in summer and drop to −20°C in winter—a 60-degree seasonal swing that helps explain why this rugged, nearly treeless landscape is such a harsh home for plants.
