Geological Sites

Area AreaSummit CalderaSummit Caldera

As you walk along the summit promenade towards Mt. Mihara, you will see on your left many small hills formed by the great eruption of 1777-78 (An'ei era). This eruption started from the summit crater and spewed out a lot of lava fountains and scoria, forming the Central Cone "Mt. Mihara". Later, lava flows spread out from the north-western foot of the mountain, rather than from the summit, creating many small hills in the area.

These lava formations are puffy, rounded or wrinkled like a rope. This surface morphology is characteristic of less viscous lava and is known as pahoehoe lava ("Pahoehoe" is a local Hawaiian word meaning "smooth").

Rope-like Lava

Picture of the Great An'ei Eruption

Location Information