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| Mt. Sakura-jima in Kagoshima-ken - back in the 1930's. Collection of Andrew Joseph |
The March 13, 2011 eruption of the Shinmoedake volcano hundreds of miles away may be linked to the Sendai quake of March 11, 2011, but can it be proven?
While one could affect the other, proving it is difficult.
The Shinmoedake volcano on Japan's southern island of Kyushu, 1,529 kilometres (950 miles) from the epicenter of 9.0 Magnitude Sendai earthquake, exploded ash and rocks up to one kilometre (2.5 miles) into the air on March 13. The volcano had begun its pattern of eruptions on Jan. 19 and several times afterward, most recently February 1 - until it's major eruption two days after the earthquake.
But, its this re-eruption just two days after the massive earthquake that has scientists (and me) wondering if the earthquake could have triggered this latest volcanic eruption,
"The last explosion event at Shinmoedake may be triggered by the shock of the earthquake," opines Nakada Setsuya (surname first) of the Earthquake Research Institute at the University of Tokyo. "Nobody can verify the relationship, however."
While no one can verify it, there is supposed to be a relationship between earthquakes and volcanoes - at least in principal.
Especially with a large earthquake (The Sendai quake is tied for the fourth strongest in recorded history), it can trigger a volcano many hundreds of miles away - according to volcanologist Frank Spera.
"These things are kind of like snakes in a box. They're ready to go, so you wouldn't need a huge push to get it going," he states. "An earthquake of this magnitude could provide that. It's not outlandish.... It's like taking a hammer and just whacking a large bell; there's going to be vibrations. The bell will continue to ring for a while."An earthquake may activate a volcano in several ways:
- the energy waves traveling through the ground may break up the hardened top of the volcano's magma reservoir, allowing the molten rock to escape;
- the earthquake causes a movement of gas in the volcano's magma that may trigger an explosive eruption - like the shaking of a bottle of Coke causes bubbles to rise;
- stress caused by earthquake can squeeze magma reservoirs, pushing the magma to the surface.
The problem is actually observing this process, as of the more than 1,500 potentially active volcanoes on Earth, only 50 to 100 have multiple sensors on them that could allow volcanologists to know what's actually going on beneath the surface of a volcano.
However - having noted all this, keep in mind that the Indian Ocean earthquake on December 26, 2004 was measured between 9.1 and 9.3 Magnitude and nearly wiped out Indonesia - not a single one of its 129 active volcanoes erupted.
On the other hand, two days after Chile's 9.5 Magnitude earthquake in 1960--the strongest earthquake of the 20th century--the Cordon-Caulle volcanoin the southern region of the country erupted after four decades ofinactivity.
The result? No one is sure if the Sendai quake caused the Shinmoedake volcanic eruption two days later. But hopefully it made for some interesting reading here.
And for the record, Japan has 106 active volcanoes.
Andrew Joseph
The photo above - of Mt. Sakura-jima, the 4th most dangerous active volcano because of its proximity to a city - was taken in the 1930s... it's not even the biggest eruption, as one in 1914 was a really devastating one. You can read more about this volcano: HERE.
The photo above is part of my personal collection - after I purchased a 1930s photo album at a garage sale in Utsunomiya-shi, Tochigi-ken back in 1991. It's my favourite purchase in Japan, and contains 184 photographs of the era. One of these days I'll scan them all in and show them all to you.
