In addition to the huge loss caused by volcanic eruption,
secondary disasters of active volcanoes during the dormant period
are also a huge threat to human beings.
Lake Nios in Cameroon, Africa was formed due to a volcanic eruption
500 years ago. On August 21st, 1986, the eruption of carbon dioxide
gas eruption killed more than 1700 people and their livestock.
The Long Valley volcano in California, America recently erupted
600 years ago. However, in 1995, the concentration of carbon dioxide
and ammonia killed a large area of pine trees and spreaded to
neighboring areas gradually. Volcanic eruptions not only damage
subexistence and proterty of people around the volcano, but also
affect aviation and climate. People have a clear memeory of
the volcanic eruption in Iceland. A mid-sized eruption caused a lull
in European aviation and chaos in global life. In 1815, after the eruption
of Mount Tambora, the spring and summer of 1816 became cold,
which was called a year without summer.
More volcanoes are found in Japan, Indonesia, Italy, New Zealand and
countries in America. There are more than 200 volcanoes in Japan,
in which one third are active volcanoes. In Indonesia,
there are over 400 volcanoes, including one fourth of active volcanoes.
The two countries have a nickname of "volcano state".