On New Year's Eve 1996, however, a spectacular eruption burst from the lake floor. An ecological catastrophe ensued. The force of the eruption created tsunami waves 30 feet in height that leveled the forest surrounding the lake. For all their destructive power, volcanoes are vital to man's existence. Volcanic gases helped create earth's atmosphere, and continue to affect its composition today.
Volcanic ash serves as a fertilizer, returning important nutrients and minerals to the soil.
The city of Petropavlovsk, the main settlement on Kamchatka, is built of concrete made from cinder of the 1945 eruption of nearby Avachinsky Volcano, which watches over the city from its post 20km to the north. The Kamchatka Peninsula is the northern link in the 2000 km Kuril-Kamchatka island arc. This region contains 68 active volcanoes, over 10 percent of the total found on land anywhere on Earth. The existence of the Ring of Fire is explained by the theory of plate tectonics. According to this theory, Earth's surface is fractured into a number of rigid plates that move in slow motion.