Formation of ash Eruption Columns GSD Particle Fall Ash Blankets Meteorology and fall Direct Sampling
Remote Sensing Models of Ashfall Case Studies Textbooks and References
Grain Size Distribution
2009
Definitions: lapilli, ash, fine ash, very fine ash
Ways to describe size distribution
Lognormal, gamma, multimodal
Total Grain size distributions
SPREADSHEET TOOLS
Movie of Lecture #4 Powerpoint only
Readings
Blott SJ and K Pye, 2001, GRADISTAT, Earth Surf Proc and Landforms 26: 1237-1248.
Rose, W. I., and A. J. Durant 2009, Fine ash content of explosive eruptions, J. Volcanol. Geotherm. Res.,doi:10.1016/j.jvolgeores.2009.01.010.
Mastin LG,et al, 2009, A multidisciplinary effort to assign realistic source parameters to models of volcanic ash-cloud transport and dispersion during eruptions, J Volcanol Geoth Res, doi: 10.1016/j.jvolgeores.2009.01.008.
Bonadonna C & Houghton BF, 2005, Total grainsize distribution and volume of tephra deposits, Bull Volc 67: 441-456.
GSD
Volcanic pyroclasts occur in deposits with a distribution of sizes. This reflects their original formation, transport and depositional history. For ashfall materials, atmospheric sorting and meteorological/microphysical processes are reflected.
Total Grain Size Distribution, El Chichon April 4, 1982
Spurr Ashfall; Cordoba
