Estimation and propagation of volcanic source parameter uncertainty in an ash transport and dispersal model: application to the Eyjafjallajokull plume of 14–16 April 2010

Data on source conditions for the 14 April 2010 paroxysmal phase of the Eyjafjallajökull eruption, Iceland, have been used as inputs to a trajectory-based eruption column model, bent. This model has in turn been adapted to generate output suitable as input to the volcanic ash transport and dispersal model, puff, which was used to propagate the paroxysmal ash cloud toward and over Europe over the following days. Some of the source parameters, specifically vent radius, vent source velocity, mean grain size of ejecta, and standard deviation of ejecta grain size have been assigned probability distributions based on our lack of knowledge of exact conditions at the source. These probability distributions for the input variables have been sampled in a Monte Carlo fashion using a technique that yields what we herein call the polynomial chaos quadrature weighted estimate (PCQWE) of output parameters from the ash transport and dispersal model. The advantage of PCQWE over Monte Carlo is that since it intelligently samples the input parameter space, fewer model runs are needed to yield estimates of moments and probabilities for the output variables. At each of these sample points for the input variables, a model run is performed. Output moments and probabilities are then computed by properly summing the weighted values of the output parameters of interest. Use Editorial responsibility: M. Manga Electronic supplementary material The online version of this article (doi:10.1007/s00445-012-0665-2) contains supplementary material, which is available to authorized users. M. Bursik (*) Department of Geology, University at Buffalo, Buffalo, NY, USA e-mail: [email protected] M. Jones Center for Computational Research, University at Buffalo, Buffalo, NY, USA S. Carn Geological and Mining Engineering and Sciences, Michigan Technological University, Houghton, MI, USA K. Dean : P. Webley Geophysical Institute, University of Alaska, Fairbanks, AK, USA A. Patra : T. Singh : P. Singla Department of Mechanical and Aerospace Engineering, University at Buffalo, Buffalo, NY, USA M. Pavolonis NOAA-NESDIS Center for Satellite Applications and Research, Camp Springs, MD, USA E. B. Pitman Department of Mathematics, University at Buffalo, Buffalo, NY, USA H. Bjornsson Icelandic Meteorological Office, Reykjavík, Iceland M. Ripepe Dipartimento di Scienze della Terra, Universita degli Studi di Firenze, Florence, Italy Bull Volcanol DOI 10.1007/s00445-012-0665-2