Geological Sites

Area AreaSummit CalderaSummit Caldera

On November 19, 1986, the lava overflowing from the summit crater flowed down the slope of Mt. Mihara and covered the older trail and stopped. The tip of the lava flow is about 5 meters thick.

The surface is composed of lumps of rough rubbly rocks. This kind of lava is called "A'a lava." As the lava flows, the surface exposed to the air cools first and solidify to a crust. However, since the inside of the lava keeps high temperature, it still moves, so that crust surface is crushed, and a lot of rugged clinker is accumulated.

The night of November 19, 1986.

Cross section of the A’a lava

Location Information