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Understanding Ash Aggregation in Volcanic Eruptions

Explore the impact of ash aggregation in volcanic eruptions, crucial for predicting their aftermath. Learn about experiments, data analysis methods, and the correlation between factors affecting aggregation efficiency. Discover insights for better eruption prediction.

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Understanding Ash Aggregation in Volcanic Eruptions

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  1. Particle Aggregation Afshan Shaikh EAS 4480 Spring 2012 April 26, 2012

  2. Importance • Ash plumes of explosive volcanism can reach upper atmosphere • Ash plume travel distance dependent on ash aggregation • Also case for volcanic vents • Pyroclastic density currents • Better understanding of eruptive flows • Help predict after math of volcanic eruptions

  3. http://www.boston.com/bigpicture/2011/06/volcano_erupts_in_chile.htmlhttp://www.boston.com/bigpicture/2011/06/volcano_erupts_in_chile.html

  4. http://www.boston.com/bigpicture/2011/06/volcano_erupts_in_chile.htmlhttp://www.boston.com/bigpicture/2011/06/volcano_erupts_in_chile.html

  5. Methods • First experiment (referred to as ‘old data’ later’) • Laser sheet • Data processed by matlab • Ash and Ballontini • Second experiment • Evacuate to simulate lower pressures • Hand processed (yay) Old experiment set up, Image obtained from Jen Telling

  6. Formulas and Assumptions • CKE ( Collisional Kinetic Energy) • Calculated differently for both experiments • Energy of the collision • Assumed densities of the ash was 2650 kg/m3 • Perfect sphere for volume calculation • Diameter • Reduced Diameter vs. Assumed Diameter • Aggregation Efficiency calculation

  7. Analysis • Used Regression analysis (RH and CKE) • For linear regression, error structures calculated and plotted (RH) • Correlation Coefficient (RH and CKE) • Boot Strap for Correlation Coefficients (RH and CKE) • Comparison of actual vs. bootstrap mean

  8. Boot Strap Correlation Coefficients (CKE) CorrCoef R = -0.7858 P = .0 BootStrap R = 0.7972 CorrCoef R = -0.5659 P = .005 BootStrap R = 0.609

  9. Boot Strap Correlation Coefficient (RH) CorrCoef R = -.2704 P = ..4499 BootStrap R = -0.2798 CorrCoef R = -.2290 P = .0.3936 BootStrap R = -0.2461 CorrCoef R = 0.0837 P = .5892 BootStrap R = 0.0807

  10. Conclusion • No significant correlation between RH and Aggregation Efficiency • Definite nonlinear regression Aggregation Efficiency and CKE

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