On this day, 46 years ago, on October 28, 1979 (September 8, 1979 in the lunar calendar), the Mount Miyue volcano in Japan suddenly erupted. On October 28, 1979, the Yuyue Mountain volcano, which had been dormant for 20,000 to 30,000 years, suddenly erupted. Mount Miyue is located at the junction of Nagano Prefecture and Gifu Prefecture in central Honshu Island, Japan, with an altitude of 3063 meters. In the early morning of the 28th, a huge roar suddenly came from the top of Yuyue Mountain, and smoke and flying rocks were immediately sprayed out. Thick smoke rushed to an altitude of 2000 meters, and flying rocks reached a diameter of 1 meter. More than 10 volcanic craters are formed on the top of the mountain, and the main crater is about 30 meters in diameter. Volcanic ash falls all over Nagano Prefecture (more than 13000 square kilometers). The volcano erupts every few minutes. There were signs before this volcanic eruption. Starting from 10 pm on the 27th, a minor earthquake was recorded at the local meteorological observatory. Since the summer of 1978, the amount of sulfurous acid gas eruptions in hot springs near the volcano has increased. Relevant Japanese authorities are paying close attention to whether the volcanic eruption will trigger earthquakes and major spouts.