Why is Akakabe red? In one word, its color can be attributed to rust. When a volcano erupts, ash floats up and about in the sky. During this process, the debris that have come in contact with the air, oxidize, and turn red. These debris fell and piled up to form this red layer.

Within this red layer, you should be able to see a layer of black. After the red layer had settled on the ground, the volcano began to leak, forming another layer that never came in contact with the air and, hence, became black.

But, there is yet another layer. It is white and runs vertically up the center of this layer. The local people refer to this as “takinobori.” Through this, you can see that, after the red and black layers formed, another eruption bursts out through the surface and settled.

Though Akakabe appears to be the result of a fault that recently broke off, this is not actually the case. This area is prone to strong winds, and in the winters, raging waves surge onto the land. Thus, the hills in this surrounding area slowly erode away and break down. In fact, it took 7000 years for this formation to become what you see today.

However, in the grand scale of things, 7000 years is not very long. Dōzen Caldera which you can see looking down from Mt. Akahage, was said to have formed 6 million years ago.