The ash, dust, gases, and lava released by volcanic explosion. The gases are volatile matter composed principally of about 90% water vapor, and carbon dioxide, sulfur dioxide, hydrogen, carbon monoxide, and nitrogen. The ash or dust is pyroclastic ejecta and lava is molten extrusive material consisting mainly of magnesium silicate. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
Entry Term(s)
Volcanic Ash
Volcanic Eruption
Volcanic Gases
Previous Indexing
Air Pollutants, Environmental (1982-1994)
Geology (1966-1979)
Natural Disasters (1982-1994)
Public MeSH Note
2009; see VOLCANIC ERUPTION 1995-2008, see NATURAL DISASTERS 1982-1994
The ash, dust, gases, and lava released by volcanic explosion. The gases are volatile matter composed principally of about 90% water vapor, and carbon dioxide, sulfur dioxide, hydrogen, carbon monoxide, and nitrogen. The ash or dust is pyroclastic ejecta and lava is molten extrusive material consisting mainly of magnesium silicate. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)
