HR: 11:45h
AN: V22A-06    [Abstracts]
TI: Discovering Eruption Dynamics via Inversion of Tephra Fallout Data
AU: * Connor, C
EM: cconnor@chuma1.cas.usf.edu
AF: Department of Geology University of South Florida, 4202 East Fowler Ave, Tampa, FL 33620 United States
AU: Connor, L
EM: lconnor@cas.usf.edu
AF: Department of Geology University of South Florida, 4202 East Fowler Ave, Tampa, FL 33620 United States
AU: Bonadonna, C
EM: costanza@cas.usf.edu
AF: Department of Geology University of South Florida, 4202 East Fowler Ave, Tampa, FL 33620 United States
AB: Reconstructing the dynamics of an eruption helps us to understand the eruptive behavior of a specific volcano. When a volcanic eruption cannot be directly or remotely observed and the resulting tephra deposit is not rapidly sampled, very basic parameters, such as plume height, grainsize distribution, erupted mass, and the prevailing wind speed and direction, cannot be determined. These crucial eruption parameters are very difficult to estimate for recent eruptions and practically impossible to resolve for older eruptions. This issue has been previously addressed by interpreting and extrapolating existing data, but recent studies have shown that such data extrapolation is not reliable for the calculation of such important parameters as the erupted mass and the total grainsize distribution. A straightforward answer to this problem is to invert observed physical volcanological data to solve for the eruption parameters directly. This set of modeled eruption parameters is continually adjusted by using the downhill simplex algorithm. Tephra accumulation must be recalculated for multiple geographical locations using a forward solution each time the set of assigned properties is changed. Calculated values are continually compared to the observed data using a goodness-of-fit test until the model parameters no longer change within a specified tolerance between successive iterations. A set of eruption parameters producing a grainsize distribution mimicking the observed distribution results. Parallelizing the inversion problem specifies a more complete solution space of possible eruption dynamics.
DE: 8404 Ash deposits
DE: 8409 Atmospheric effects (0370)
DE: 8419 Eruption monitoring (7280)
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2005 Joint Assembly