TsukuBlog

A Local Perspective on Life in Tsukuba, Ibaraki, Japan.

There are no more DORMANT or EXTINCT Volcanoes in Japan- only ACTIVE ones- something to consider before you head off to the mountains!

 

Mt. Fuji has not erupted in more than

Mt. Fuji has not erupted since 1707, but it now considered active- not because it has been showing signs of stirring, but because ALL volcanoes that have erupted anytime in the past 10,000 years in Japan are now defined as active and can in fact erupt at any time without warning.

By Avi Landau

環太平洋造山帯 (KANTAIHEIYO-ZO-ZANTAI).  A long string of kanji characters – and a mouthful to say, as well – but one of the first Japanese words I ever learned, from my favorite beginner`s Nihongo textbook: “Nihon no Chiri – Japanese Geography”. It is also one of the Japanese words that has always stuck out most in my mind- because it was one of my earliest, and because in this land of incessant earthquakes and volcanic activity, it is so appropriate. You see, along with it`s alternate moniker: KANTAIHEIYO-KAZANTAI (環太平洋火山帯), it is the Japanese word for what in English is referred to as the circum-Pacific orogenic zone, the circum-pacific belt, or more commonly- the Pacific Ring of Fire.

The Pacific Ring of Fire

The Pacific Ring of Fire- the distorted upside-down horseshoe along which most of the world`s major earthquakes and volcanic eruptions occur

Something else that has been deeply ingrained in my mind since my days of studying “Japanese Geography” was that there were three types of volcano in Japan:

KATSU KAZAN (活火山)- active volcanoes : such as Mt. Sakurajima in Kagoshima Prefecture which erupts thousands of times a year,

KYU- KAZAN (休火山)- dormant volcanoes: such as Mt Fuji for which there is historical evidence of past eruptions though no activity in the present day,

and

SHI KAZAN (死火山)- extinct volcanoes: mountains which are geologically deemed to be volcanoes for which there are is no historical evidence of eruption.

For me these made for a mighty triumverate of terms as familiar as the names of the Ten Plagues, the Seven Dwarves or the Three Stooges.

Mt. Fuji`s last eruption

Mt. Fuji`s last eruption in 1707. Though the Japanese archipelago makes up only 0.25 of the Earth`s terrestrial surface, nearly ten percent of the worlds active volcanoes (110 of them) are located within its borders,

But alas, as if they were trying to mock my years of hard study, the powers that be, went and changes these iconic designations (just as after I had finally learned the names of all the towns around Tsukuba: Mitsukaido, Iwai, Shimodate, Makabe the names were suddenly changed respectively to Joso City, Bando City, Chikusei City, and Sakuragawa City).

No matter how hard it is for me accept it, the Meteorological Agency of Japan has decided to eliminate the terms DORMANT VOLCANO and EXTINCT VOLCANO.

Climber caught fatefully off guard on Mt. Ontake

Climbers caught fatefully off guard on Mt. Ontake on September 27, 2014. It goes to show that you can NEVER tell when a volcano is going to erupt. Until 1979 this volcano had been considered extinct.

Despite my feelings about the matter, I realize that the changes in definition are prefectly logical and sensible.

Take for example the case on Mt. Ontake which erupted last year (September 27, 2014) killing more than 50 people. Since there had been no historical evidence of eruption and no activity in modern in modern times,  the second highest volcano in Japan was considered extinct until October of 1979 when began to erupt and emit large amounts of ash.

The deadly eruption of 2014 then came without any warning at all.

This all goes to show that you cannot rule out the possibility of eruption at ANY volcano at ANY time- and that is why the Meteorological Agency of Japan decided to do any with the designations dormant volcano and extinct volcano.

Any volcano which has shown sign of acitivity in the last 10,000 years are now considered active (there are 110 such volcanoes in Japan- nearly ten percent of the world total) while volcanoes which have been inactive for longer than 10 thousand years and have no magma beneath them are considered…… well…… just plain mountains.



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