An eerie gray smoke billows up from the crater. The huge plume quickly covered the sky and rose to a height of 3,500 meters. People in the parking lot just below the crater rush inside the building.
At 11:43 a.m. on October 20, Mount Aso (1506 meters high) in Kumamoto Prefecture erupted. It was the first eruption of Mount Aso in five years, since October 2004. A pyroclastic flow also occurred about 1,300 meters to the west of the crater. At 12:44, just after noon, there was a second explosion. The Japan Meteorological Agency raised the eruption alert level from 2 to 3 and declared the area around the crater 2 km off-limits.
What was the cause of the eruption? Manabu Takahashi, a specially appointed professor at Ritsumeikan University who specializes in disaster risk management, explains.
“Due to the Great East Japan Earthquake that occurred in March 2011, the Pacific Plate had been moving from west to east. In September of this year, there was a change in the movement. The Pacific Plate is now being pulled to the southwest.
This put pressure on the Kyushu and Okinawa regions, and volcanic activity increased. Due to the pressure from the east, the magma that had accumulated underground must have popped out onto the surface. In addition to Mount Aso, Satsuma-Iwo Jima and Kuchinoerabu Jima require attention. Sakurajima, in particular, has had 1,300 eruptions recently, compared to the usual 50 to 100 per year.
When the plates spring up: ……
The movement of the Pacific Plate has a major impact on the entire Japanese archipelago. As a result of the tectonic movement, other areas are also at risk of disasters. Mr. Takahashi continues.
“The magma in the ground along the Izu-Ogasawara Trench is also under a lot of pressure. There is a possibility that the magma may not be able to withstand the pressure as in the case of Mount Aso, and may erupt.
The area where the strain is most concentrated is from Hamanako in western Shizuoka Prefecture to Toyohashi in eastern Aichi Prefecture. The Pacific Plate is moving to the southwest and is trying to get under the Eurasian Plate in this region. If the Eurasian Plate can no longer withstand the pressure of the Pacific Plate and the boundary area springs up, we will be in big trouble. There will be a big earthquake. It’s a Tokai earthquake.
If a Tokai earthquake occurs, there are concerns about the impact on Mt.
“Fuji will erupt because of the effects of a major earthquake. The last time it exploded was in 1707, about 300 years ago. A major earthquake occurred a few dozen days before this great eruption of 1707. Based on records from that time, it is believed that this was the Tokai Earthquake.
If you look at Mt. Fuji from the sky, you can see that there is not just one crater, but a series of them. If these craters were to erupt in tandem, the damage to not only the Kanto and Tokai regions, but the entire Japanese archipelago would be immeasurable.
Japan is a country formed by volcanoes. Japan is a country made up of volcanoes, and eruptions and earthquakes can occur at any time. With the eruption of Mt. Aso, we should be aware that the risk of a major disaster has increased even further.
photo： Kyodo News