Hagi Geopark and Tatamigafuchi – spots created by volcanic activities.

Have you ever heard of “Hagi Geopark”?
“Geopark” means a place where you can learn about and enjoy “geo” (“earth” in Greek).
Actually, the northern part of Yamaguchi Prefecture is a land which was created by volcanic activity between about 100 million and 10 thousand years ago.
There are several spots where you can actually see this sort of dynamic topography, and the “Hagi Geopark” was designated as one of 44 of “Japan Geoparks” (as of 2019).

“Tatamigafuchi” is one of the highlights of “Hagi Geopark.”
The geographical features of Tatamigafuchi were created by the volcanic activity of Mt. Irao, which is close to this place, about 400 thousand years ago.
A stream of lava flowed down along the river, and it created this kind of unique topography.

You can reach the river after a 5-minute-walk from the parking lot.
You will find a kind of mysterious space with a riverbed are all covered by hexagonal cylinder rocks.

Also, a precipitous cliff of columnar joint stands on the stream bank.
A columnar joint is a crack forming the shape of a pillar on rock, and this is formed when lava cools off and solidifies.

The hexagon-shaped rocks cover the surface of a riverbed so tightly, that each one seems like part of a tortoise shell.
But these are also some columnar joints which were scraped away by the river’s flow over a long, long time.

There is a small waterfall with a height of about 2-3 meters downstream.
Finally, you arrive at “Tatamigafuchi,” and will be surprised by the breathtaking beauty of the big emerald green water pool surrounded by the wall of columnar joints.

This pool is at the frontline of where lava is now being eroded by water, therefore, this waterfall is gradually receding.

The columnar joint continues to the other side of the river, where a small shrine is standing.

Not only the rock covering the riverbed, but also the cliffs of columnar joints on the both side of the river, are worth seeing.

The hexagonal rocks can be seen on the riverside for a distance of about 2km, so it would be nice to take a stroll upstream.
The view of water flowing between the unusually shape rocks is quite unique.
And you can enjoy mountain stream fishing here in summer.

How about a trip visiting other geosites at Hagi Geopark?

There are a lot of spots designated as part of “Hagi Geopark,” and they are mainly located on the coast of the Japan Sea.
So we recommend that you take a trip to visit these geosites.

Of special note is “Susa Hornfels,” a wonderful viewing spot located in the northwestern part of Yamaguchi Prefecture.
This cliff with black and white stripes is the must-see!
White parts were originally sand layers, and the black parts were mud layers.
Magma with a high temperature flowed into the layers and the heat turned the layers into a cliff of metamorphic rock.

You might be able to feel the heartbeat of the earth by seeing these dynamic views in the northern part of Yamaguchi Prefecture!
Why not take a trip to visit these geosites at “Hagi Geopark”?

Photographs and text by Hironobu Matsuoka