Ayutsubo Waterfall

Ayutsubo no Taki is a beautiful waterfall about 9 meters high and 65 meters wide that cascades from a cliff where lava flows from Mt.

Fuji, AYUTSUBO NO Taki is a beautiful waterfall that cascades from a cliff approximately 10 meters high and 90 meters wide.

Normally, the waterfall flows down from two points, and the view of it cascading down between the lava rocks is magnificent, especially when viewed from the “Ayubotsubo no Kakehashi (bridge over the Ayubotsubo)”.

It was designated as a natural monument by Shizuoka Prefecture in 1996, and is also a Geo-Site of the Izu Peninsula Geopark.

This waterfall was formed by the eruption of Mt. Fuji about 10,000 years ago, and the Aitaka Loam Formation lies beneath it.

Lava tree formations can also be seen at the bottom of the bedrock. Located downstream of the Makiyan Bridge, the falls appear as a single waterfall during drought and as up to four waterfalls when the water level rises.

Name

There are several theories as to the origin of the name “Ayu-tsubo. Some say that it was named after the ayu (sweetfish) that swarmed in the waterfall basin at this waterfall, while others say that it was called “Aizubo” because the deep waterfall basin looked blue.

Locals sometimes call it “Aitsubo. There was a time when it was described as “Aizubo no Taki” (Aizubo Falls), and it was also called “Fujimi no Taki” (Fujimi Falls) because of its view of Mt. Numazu City’s official website and tourist portals refer to it as “Ayutsubo.

Geology

Ayutsubo Falls was formed by the process of filling the valley between Mount Aitaka and Mount Hakone with 80-meter-thick lava called Mishima lava from the eruption of Mount Fuji about 10,000 years ago. This waterfall is located at the western end of one lava flow, and the thickness of the lava at the point of the waterfall is about 8 meters.

The rock type is basalt, with plagioclase being prominent. An 8-meter-high lava tree formations can be seen at the bottom of the waterfall, and the central loam layer of the Aitaka Loam Formation can be seen beneath the eroded volcanic ash layer at the bottom of the lava bed.

Rope-shaped lava can be seen on the riverbed above the waterfall. Nawa lava refers to the characteristic shape of lava that hardens into wrinkles depending on the direction in which the lava flowed and looks like a bundled rope.

In the vicinity of Ayubotsubo Falls, lava mounds and rope-shaped lava rocks created by lava flows can be seen in the precincts of Waritsuzuka Inari Shrine. Lava mounds are dome-shaped landforms formed when the interior lava that flowed out later pushed up against the surface shell formed by the cooling and solidification of hot lava.

History

Ayubotsubo Falls is believed to have been formed during the Jomon Period when the sea level, including the Kisegawa River, dropped, causing the lava layer to break apart and form an 8-meter-high waterfall.

Waterfalls and Life

The Kise River is also important as a water supply, and many weirs, sluice gates, and flumes have been installed. A water channel for rice cultivation was drawn from Ayubotsubo Falls, and in 1603, Saburobe Amano excavated the Honjuku Weir to draw water for Honjuku, but there was another weir just upstream, and the location of the water source was disputed for many years. The waterfalls and park are located in the center of the city.

Waterfall and Park

Downstream of the falls, on the Nagaizumicho side, Ayubotsubo Park was established in 1981, while the Numazu City side was developed as a green area. A suspension bridge has been built between the two, from which the falls can be viewed from a mid-river perspective. The main administrator of the falls is Nagaizumi-machi, and in 1998 the “Ayubotsubo no Kakebashi” bridge was completed across the river between Nagaizumi-machi and Numazu-city.

Tradition

There is a legend about Ayubotsubo Falls called the “Legend of the Turtle Crane. A long time ago, there was a woman named Kamekaku, a beautiful daughter of the chief of Kisegawa-juku (present-day Numazu City).

In 1293, Minamoto no Yoritomo heard of Kamekaku’s beauty and tried to invite her to join him on his hunt for the Fuji rolls, but Kamekaku did not accept his invitation and instead threw herself into the Ayubotsubo Falls.

Another theory is that Kamekaku was invited to Kudo Suketsune’s house, but was involved in a revenge attack on the Soga brothers, so she ran away and threw herself into the Ayubotsubo Falls.