Japan’s Mount Aso Erupts, Alert Level 3 Issued In Kumamoto Prefecture

The large-scale explosion of Mt. Aso in Japan was due to volcanic gases and vapors rapidly building underground, seismologic experts said. The eruption, which included large-scale air vibrations at the volcano as well as in parts of Kumamoto Prefecture was said to be the first of its type in 36 years.

Makoto Saito of the Volcanology Division of the Japan Meteorological Agency said, "Concerning Mt. Aso, it is extremely rare for the height of the columns of volcanic smoke to exceed 10,000 meters." Yet, the earthquake-like tremors reported in the nearby areas left in its wake volcanic ash that fell on the Shikoku region.

The Chicago Tribune noted that expert believe the eruption to be likely a phreatic explosion - where underground water was boiled by magma heat, causing an explosion of such great power - up to over 11,000 meter in the air.

Images from the area showed that volcanic ash coated steets, roofs, and vehicles, although CNN pointed out that there had been no injuries reported. For safety, however, the alert level was raised to 3, with the highest being 5, with a warning to the members of the public not to approach the mountain, and to consider falling rocks.

Saito also warned that while still in the active phase, there is a possibility of the volcano giving another eruption of the same scale. Professor Takahiro Okura of the Aso Volcanological Laboratory of Kyoto University, an expert on volcano physics, added that ash deposits have also been scattered across several areas several hundred meters away from the actual volcanic vent, some of which are the size of pickup trucks. He believed that such eruption was caused by underground pressure that rose rapidly just before the volcano erupted early last Saturday.

Japan, a country that sits on the "Pacific Ring of Fire" has active volcanoes scattered all around its islands: this year alone had the country issuing level 3 alerts for the Sakurajima and Kuchinoerabujima volcanoes as well.