Sub-tropical Lava Coast
Not far from the Abunze Visitor Center, a path leads downhill toward the ocean. Following this path brings you to a coastline unlike most in Japan. To get a better view, climb to the top of the observation tower. Behind you is the truncated form of Mt. Onidake, the largest mountain in the area, and if you look in both directions along the coast, you can see long stretches of dark black rocks at the water’s edge. Although the approach to the coastline is green and covered with flora, that stops abruptly, and there is no vegetation on these rocks.
A Recent Eruption
Blackened rocky coastlines are nothing unusual in the Goto Islands, but the Abunze Lava Coast has a special history. Some 18,000 years ago, when Onidake or another nearby volcano erupted, some of the lava from that event flowed down to this spot.
This type of lava, known as a’a, is rough in texture. When it cools, it creates large, uneven, black rocks, many pockmarked with holes where gas escaped from the solidifying ooze. This a’a lava also produces sharp, black fragments called clinkers, which are visible here among the larger rocks. Over the millennia, these all suffered erosion from the pounding ocean and were broken down further, creating a broad stretch of volcanic rocks of all sizes and shapes.
The eruptions of Mt. Onidake and some other nearby volcanoes produced just such a phenomenon, creating this 7-kilometer-long jagged coast with more than half a dozen tiny bays. Today, thanks to the Tsushima Current, the Abunze Coast is the warmest place on the island. There are even subtropical plants growing here.
Feudal Lord’s Escape Route
One more unusual element here is the name: the characters mean something like “stirrup shallows,” which implies that this coastline has some connection with horses. According to an old story, a local lord tried to escape an uprising against his rule back in 1507. Fleeing on horseback, he rode along the coast, but just at this point one of his stirrups broke and he was forced to escape in a fishing boat to a nearby island. Ultimately, he killed himself rather than be captured. Thus was born the legend of “stirrup shallows.”
Regardless of the old historical tales, the spot is definitely worth a visit, either before or after checking out the Visitor Center nearby to get an overall picture of the Goto Islands, their geography, wildlife, flora, and geological origins.