Volcano Hazards - 5 of 8

Volcano Hazards FAQs - 8 Found

How are lahars formed?

Lahars are commonly initiated by: 1) large landslides of water-saturated debris, 2) heavy rainfall eroding volcanic deposits, 3) sudden melting of snow and ice near a volcanic vent by radiant heat or on the flanks of a volcano by pyroclastic flows, or 4) breakout of water from glaciers, crater lakes, or from lakes dammed by volcanic eruptions. Since 1980, lahars have formed by all of these processes at Mount St. Helens. -- From: Brantley and Power, 1985, Reports from the U.S. Geological Survey's Cascades Volcano Observatory at Vancouver, Washington: Earthquake Information Bulletin, v.17, n.1, January-February 1985.
