Base Surge 3 : Turbulent, low-density cloud of rock debris and water and (or) steam that moves over the ground surface at high speed. Base surges are generated by explosions. (Miller, 1989)
U.S. Department of the Interior, U.S. Geological Survey, US Geological Society (USGS), Glossary of Volcano and Related Terminology, USGS/Cascades Volcano Observatory, Vancouver, Washington, USA 2006. http://vulcan.wr.usgs.gov/Glossary/volcano_termino logy.html, (ND/ Volc Sci - Amer) {493}