Surface Events : Surface Events, such as gas and tephra events, rockfalls associated with dome growth, and snow and rock avalanches from the crater walls, which produce complicated signatures with no clear beginning or end
Natural and Environmental Disaster Information Exchange System NEDIES, European Commission, Directorate General Joint Research Centre (DG JRC), Institute for the Protection and Security of the Citizen (IPSC), Ispra (Varese) Italy, http://nedies.jrc.it/index.asp?ID=82#Top, US Geological Survey (USGS), Earthquake Hazards Program, Glossary of Earthquake and Related Terminology, USGS/Cascades Volcano Observatory, Vancouver, Washington, Washington, USA 2012. http://vulcan.wr.usgs.gov/Glossary/Seismicity/eart hquake_terminology.html, (ND/ Erthq - Amer) {165}