Eruption Source Parameters: Improved input to volcanic-ash dispersion models. (Marianne Guffanti, USGS, 4 June 2008) In support of a long-standing interest of the ICAO, the USGS established a project in 2007 at the Cascades Volcano Observatory (CVO) to analyze eruption source parameters (ESP) for use in atmospheric volcanic-ash transport and dispersion models. Project lead is Larry Mastin. The relevant ESP include: –plume height above the vent –eruption duration –mass eruption rate –erupted volume –mass fraction of erupted debris whose grain size is <63 microns. Per ICAO guidance, outcome of the analysis will be a matrix of ESP for various types of eruptions that can be readily used as default input values by ash-dispersion modelers at the Volcanic Ash Advisory Centers (VAAC) when data from a particular eruption were not available.

The ESP project was launched with a workshop at CVO on April Attending were reps from IUGG VAAC Montreal VAAC Washington NOAA’s Air Resources Lab. U.S. Air Force Weather Agency Smithsonian Institution Alaska Volcano Observatory Cascades Volcano Observatory academia Subsequent to the workshop, ESP working group was broadened to include representatives from VAAC Darwin, and other international researchers Outcome of 4/2007 workshop was a wiki (editable web pages) at to share information and track accomplishments. To get a user id and password for login, contact Peter Webley (UAFGI) at

To gather existing ESP-related data, information on well- documented eruptions is assembled on the wiki. St. Helens, USA, May 1980 El Chichón, Mexico, March-April 1982 Galunggung, Indonesia, June 1982 Pinatubo, Philippines, June 1991 Mount Redoubt USA, December 1989-April 1990 Cerro Hudson, Chile, August 1991 Spurr, USA, August and September 1992 Kliuchevskoi, Russia, September 1994 Rabaul, Papua New Guinea, September 1994 Ruapehu, New Zealand, June to August 1996 Hekla, Iceland, February 2000 Miyakejima, Japan, August 2000 Nyamuragira, D.R. Congo, July 2002 Ruang, Indonesia, September 2002 Etna, Italy, Oct 2002 to Jan 2003 Reventador, Ecuador, November 2002 Popocatepetl, Mexico, February 2003 Manam, Papua New Guinea, Oct 2004 to Jan 2005 Grímsvötn, Iceland, November 2004 Karthala, Comoros, November 2005 Augustine, USA, January 2006

How to Use ESP: Based on data from the well-documented eruptions, the working group established a matrix of 11 eruption types with ESP assigned to each type.

For each of the ~1500 volcanoes in the Smithsonian Institution’s global volcanism database, a default eruption type and its attendant ESP values then were assigned by the working group on a preliminary basis. This information is viewable as a spreadsheet at and on a map interface at The spreadsheet fulfills the objective of providing readily available input ESP for immediate use by forecasters in ash transport and dispersion models. If an actual eruption differs from the eruption type that has been assigned as the default type, then forecasters should go to the classification matrix of eruption types with ESP values and choose the appropriate type. Also, forecasters should incorporate any actual observations or data related to ESP, such as plume height, into additional model runs. How to Use ESP, cont’d.

Next step in the ESP project is to seek additional review and correction of the data in the spreadsheet described above. Final product (including explanation of how to use the material) will be included in ICAO’s Handbook on the International Airways Volcano Watch: Operational Procedures and Contact List, Document 9766 ( Document 9766) where it can be updated as additional ESP data and eruption information are obtained (e.g, for recent eruption of Chaiten in Chile). Also, a paper by Mastin et al. is being submitted to the Journal of Volcanology and Geothermal Research.