OREGON STATE UNIVERSITY

Mt Ontake Eruption: Japan Remembers One Year Anniversary

It was the 27th of September, 2014. The people visiting and living around Mt Ontake, Japan had no reason to suspect anything was amiss; they had just started their weekend and it was a beautiful Saturday morning.

Mt Ontake, a popular destination for hiking, had not shown any signs of the building energy beneath the surface. There had been no earthquakes in the region to alert officials to the explosion that was going to happen.All was peaceful; several tourists were hiking up and down the safe slopes, unaware of what was soon to strike.

Mt Ontake, located on the island of Honshu, Japan, is one of the many active volcanoes belonging to Japan. Mt Ontake, along with many other Japanese volcanoes such as Mt Fuji, forms an iconic conical shaped stratovolcanoes.

Japan, located on a triple junction, is the product of the Philippine and Pacific Plate subducting beneath the Eurasian Plate. The subducted crust is heated up, melts, and creates buoyant magma that then rises and erupts as island arc volcanoes that form the nation of Japan.

 

Figure above: Japan lies at a triple Junction

The eruption at Mt Ontake happened quickly and struck hard. At around 11:50am, Mt Ontake exploded, injuring and stranding hikers on its slopes. Although some hikers miraculously managed to seek shelter while waiting for rescue, several were buried under the ash, while many more perished.

This eruption marked the most deadliest eruption in Japan since Torishima in 1902, and was the first deadly eruption in Japan since Mt Unzen in 1991. Search and rescue efforts continued till the 4th of October, but were then halted from the 5th to 6th of October as Japan was struck by Typhoon Phanfone. The last of the rescue efforts ended around the 11th of October; the death toll was officially reported at 57 lives, while 6 lives were still missing.

 

Video: Mt Ontake's eruption on 27 September, 2014

 

This past week, on the 27th of September, 2015, Japan remembered the one year anniversary of this deadly eruption. The explosion at Mt Ontake serves to remind us of the deadly and strong force that volcanoes are, and the unpredictable nature of the Earth.

No one could have foreseen this eruption; there were no geological indicators to suggest that an eruption was going to take place. Such eruptions and activities on Earth's surface only justifies our need to continue studying volcanic processes, to better understand what goes on beneath our feet, and perhaps one day be able to predict natural disasters before they occur.

 

For more information on this eruption, as well as pictures and first hand accounts from survivors, check here.

More on the eruption events, check here and here.