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).

In this article, we suggest you a trip visiting some highlights (geosites) of “Hagi Geopark”!

The former Meirin Elementary School was closed in 2014, but the wooden building was renovated and opened as “Hagi Meirin-Gakusha,” a base for sightseeing in Hagi.
It introduces the history, culture, and natural wonders of Hagi.

You can learn about the mechanism by which Hagi’s topography was created here (English translations available).
So, it is recommended that you to stop by here before you go visit some of the geopark sites, as you will be able to understand the sites much more.

Mt. Kasayama, located in northeastern part of Hagi City, is a volcano with a height of 112m.
At that altitude, it is also called “The smallest volcano in the East.”

There is a crater with a diameter of 30m and a depth of 30m on the top of this mountain, and actually, you can climb down into the crater.

There are some flat islands, such as Oshima, Ainoshima, and so on, and these islands are called the “Hagi 6 islands.”
You can see these islands from the observation tower on the top of Mt. Kasayama.
This is a rare spot which you can see the small lava plateaus made of andesite floating on the sea, and this is the only spot like this in the whole world.

Kasayama
Address／1189-652, Chinto, Hagi-shi, Yamaguchi
Phone／0838-25-3139 (Hagi City Tourism Division)
http://hagishi.com/search/detail.php?d=100055

Kiyogahama is a well-known beach which has “singing sand.”
Singing sand produces sound when stepped on, and it is also called “whistling sand” or “squeaking sand.”
Tiny superfine quartz grains produce surface friction when people walk on this beach, and that creates the squeaking sound.
These sands were originally granite magma which eventually chilled and solidified, and after long exposure to wind and rain became sand.
Therefore, this “singing sand” is also a product of the ancient volcanic activity.

The next spot is “Tatamigafuchi.”
You can see the cliffs of columnar joints on the both side of the river.
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 emerald green color of the water pool surrounded by the wall of columnar joints is stunningly beautiful!

Let’s head north again, and go to “Mt. Kouyama,” standing on northeast side of the Gulf of Susa.
This mountain was made of magma which rose because of the eruption of a submarine volcano.
The altitude is 532.8m, and an access road reaches nearly to the top of the mountain.

Kouyama
Address／7030 Susa, Hagi-shi, Yamaguchi
http://kanko.susa.in/weblog/tennenkinenbutu-2/kouyama/

“Susa Hornfels” is a wonderful viewing spot located on the northeastern part of the Gulf of Susa, and the cliff with its black and white stripes is a must-see!
The white parts were originally sand layers, and the black parts were mud layers.
High temperature magma flowed into the layers and the heat turned the layers into a cliff of metamorphic rock.

After the sunset, you can see this sort of fantastic scenery of the cliff with the twilight color of the Japan Sea and sometimes the fishing lights used for squid fishing.

Susa Hornfels
Location／Susa Koyama Kitakaigan, Hagi City, Yamaguchi Prefecture
http://www.hagishi.com/search/detail.php?d=1100198
Reference： Homepage of Hagi Geopark Promotion Council
https://www.city.hagi.lg.jp/site/hagigeo

Photographs and text by Hironobu Matsuoka