Large plinian eruptions sometimes result in the withdrawal of so much magma from below a volcano that part of it collapses to form a large depression called a caldera.
A few well known plinian eruptions of the 20th century include Mount Spurr, Alaska (June 27, August 18, and September 16-17, 1992); Mount Pinatubo, Philippines (June 15, 1991); El Chichón, Mexico (March-April 1982); Mount St. Helens, Washington (May 18, 1980); Agung volcano, Indonesia (March 17, 1963; and Novarupta, Valley of 10,000 Smokes, Alaska (June 6, 1912).
Some plinian eruptions inject such large quantities aerosols (small liquid droplets) into the stratosphere that surface temperatures on Earth may decrease slightly. A few recent eruptions resulted in detectable cooling – the 1991 eruption of Mount Pinatubo, Philippines, and the 1982 eruption of El Chichón, Mexico. The massive 1815 eruption of Mount Tambora volcano, Indonesia, is thought to have caused the 1816 "Year without a Summer" in the northeastern U.S., Canada, and western Europe.
Related category GEOLOGY AND PLANETARY SCIENCE
Source: U.S. Geological Survey
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