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Introducing Tamagawa Hot Springs

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  • Location: Coventry,Warwickshire
  • Location: Coventry,Warwickshire

My intention is to produce a series of articles (depending on interest) which introduces ideas about volcanic and earthquake activity. I want to go slightly off the beaten track to explore oddities, volcano hazards, analysis methods, Wonders and Mankind’s impacts. Keep in mind I am not expert (corrections gratefully received), but hopefully these will at least give a flavour of some different places in the world and provide a few minutes escape from people’s troubles.

Introducing Tamagawa hot springs



Reason for Interest
Not all Volcanoes are big or threaten big eruptions, but some have anomalies which are curious and may represent threats which are not obvious. Volcanoes which produce acidic radioactive hot springs and have mud eruptions could leach dangerous contaminates into rivers with unknown consequences. This will be another short post due to the shortage of information.

The Hot Spring
Tamagawa Hot Spring located at the base of Mount Akita Yakeyama is a hot springs in Japan with the largest discharge from a single source (9,000 litres per minute) and also boasting the most acidic spring water Japan.


 Temperatures reach  98 Degrees and due to deposits of radioactive hokutolite near the spring, the water is also slightly radioactive. Tamagawa Onsen has just a single ryokan with a large number of simple rooms and a public bath, where guests can either stay overnight or use the bath on a day visit. More than other Japanese hot spring resorts, Tamagawa Onsen attracts a large percentage of guests who primarily come for health reasons.


The Volcano
Akita Yakeyama is a small stratovolcano, approximately 7km in diameter, and with a relative height of approximately 700m. A summit crater 600m in diameter is located at the summit area, and the Yakeyama summit is located on it south western rim. The volcano has two lava domes. A flank volcano, Tsugamori, is located on the eastside of the main volcanic edifice, discharging lava to the east. Another flank volcano, Kuroishimori, is located on the other side of the main volcanic edifice. Tamagawa Onsen which is located at the western foot of the volcano.


Eruption history
The Tsugamori western lava dome was formed at the summit approximately 2,500 years go. This was followed by, at least, three phreatic eruptions which occurred around the summit, in the 14th to 15th century, 15th to 17th century, and after the 17th century. Several small phreatic eruptions whose deposits have not been preserved are considered to have occurred within the historical period, but details of them are not known.

Recent activity
During May 1997 there was a land slide and Phreatic Eruption. The land slide reached the top of the hot spring. On the following day there  was a large collapse occurred on the same flank. Steam discharge and ash fall were observed at the collapse site. 

In August 1997 there was a small phreatic eruption in the southeast of Karanuma, near the summit. Mountain climbers witnessed a volcanic plume. Muddy volcanic ash was sprayed up to 300m south of Karanuma. 

I am not convinced of any real threat from this environment but it is sufficiently odd to warrant a few words.




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