Tephra Transport, Sedimentation and Hazards Alain C

University of South Florida Scholar Commons Graduate Theses and Dissertations Graduate School 3-31-2009 Tephra Transport, Sedimentation and Hazards Alain C. M Volentik University of South Florida Follow this and additional works at: https://scholarcommons.usf.edu/etd Part of the American Studies Commons Scholar Commons Citation Volentik, Alain C. M, "Tephra Transport, Sedimentation and Hazards" (2009). Graduate Theses and Dissertations. https://scholarcommons.usf.edu/etd/71 This Dissertation is brought to you for free and open access by the Graduate School at Scholar Commons. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Scholar Commons. For more information, please contact [email protected]. Tephra Transport, Sedimentation and Hazards by Alain C. M. Volentik A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy Department of Geology College of Arts and Sciences University of South Florida Co-Major Professor: Charles B. Connor, Ph.D. Co-Major Professor: Costanza Bonadonna, Ph.D. Diana C. Roman, Ph.D. Jeffrey G. Ryan, Ph.D. Paul H. Wetmore, Ph.D. Date of Approval: March 31, 2009 Keywords: Tephra fall, Plinian eruptions, sedimentation models, inversion techniques, terminal velocity, Pululagua, volcanic hazards, probabilistic models, critical facilities, Bataan Peninsula Philippines c Copyright 2009, Alain C. M. Volentik DEDICATION To my wife Jasmine, my parents Christiane and Jacques, Dany and Elda & Micoul, my brothers, Kevin, Pierre-Antoine & Frédéric,and sister, Julie, and my invaluable friends, Remo, Loyc and Becs. In memory of Stéphanie ACKNOWLEDGMENTS I would like to thank my co-advisors Dr. Charles Connor and Dr. Costanza Bonadonna for giving me the opportunity to join the Departement of Geology at USF and to work on exciting research topics such as tephra fallout modeling and volcanic hazards. I also would like to thank the rest of my committee members, Dr. Diana Roman, Dr. Jeff Ryan and Dr. Paul Wetmore for their support throughout these four years. Mauro Rosi's guidance in the field was crucial in the success of this study. I hereby thank him very much for sharing his knowledge of Pululagua deposits and about tephra fallout processes in general. A special thanks to Laura Connor for her invaluable help and advice with computational problems. I am very thankful to the Istituto Geofisico in Quito, especially Pathy Mothes, Minard Hall, Gorky Ruiz, Diego Barba, and Daniel Andrade for their logistic support during my fieldwork. Additional field support from Martin Jutzeler, John Petriello, Rebecca Carey and Bruce Houghton is also acknowledged. I am also very grateful to John Scott for his precious help in the lab with grain size and grain shape analysis. My office mates and friends from the volcanology group, Heather, Mandie, Sophie, John P., Armando, Koji, Wayne and John O., have always been very supportive as well. It was a pleasure sharing ideas, discussing problems and hanging out with you guys. A special thanks to Mikel who proved to be more than an office mate and colleague, but also a great friend. I recall countless hours of tennis challenges, liters of beers and endless philosophical discussions. Paolo and his crew at the "Grotto Madonna della Fontana" in Ascona (Switzerland) are also acknowledged for hosting me two summers in a row. A special thanks also to Mary Haney and Mandy Stuck for their help and guidance through the meanders of administration. I am also grateful to the National Science Foundation (NSF) for partially funding my research (Grant EAR-0130602) and to USF for a Graduate Assistant Scholarship. Last but not least, thanks to you, Jasmine, for all the support, patience and love you gave me in this long journey that is the Ph.D. Ti amo tantissimo. TABLE OF CONTENTS LIST OF TABLES iv LIST OF FIGURES v ABSTRACT xiii CHAPTER 1 INTRODUCTION 1 CHAPTER 2 MODELING THE CLIMACTIC PHASE OF THE 2450 BP PLINIAN ERUPTION OF PULULAGUA VOLCANO, ECUADOR 7 2.1 Introduction 7 2.2 Geological setting 8 2.3 New stratigraphy 11 2.4 Empirical determination of eruptive parameters 15 2.4.1 Sample grain size and total grain size distribution 15 2.4.1.1 Grain size 15 2.4.1.2 Total grain size distribution 22 2.4.2 Erupted volume 25 2.5 Analytical determination of eruptive parameters 28 2.5.1 Erupted mass 29 2.5.2 Column height 33 2.5.3 Total grain size distribution 37 2.5.4 Uncertainty analysis 37 2.6 Mass discharge rate and eruption duration 38 2.7 Particle path 39 2.8 Forward modeling 41 2.9 Plume dynamics 41 2.9.1 Corner position 41 2.9.2 Strong plume model 48 2.10 Discussion 50 2.10.1 Statistical vs. numerical determination of eruptive parameters 50 2.10.2 Plume dynamics 54 2.10.3 Diffusion coefficient 55 2.10.4 Wind or no wind? 56 2.11 Conclusions 57 i CHAPTER 3 INFLUENCE OF PARTICLE SHAPE ON TEPHRA DISPERSAL 60 3.1 Introduction 60 3.2 Methodology 63 3.3 Particle shape 65 3.3.1 Bulk results for each φ class 65 3.3.2 Results as a function of each φ class and distance from the vent 66 3.4 Terminal velocity 73 3.4.1 Comparison between different models 73 3.4.2 VWH /VKL vs AR 77 3.5 Sedimentation 80 3.6 Discussion 84 3.7 Conclusions 88 CHAPTER 4 ASPECTS OF VOLCANIC HAZARDS ASSESSMENT FOR THE BATAAN NUCLEAR POWER PLANT, PHILIPPINES 90 4.1 Introduction 90 4.2 Volcanic setting 93 4.3 Assessment of volcano capability 96 4.4 Estimating screening distance values 99 4.4.1 Hazards from tephra fallout 100 4.4.1.1 Deterministic analysis 101 4.4.1.2 Probabilistic analysis 109 4.4.2 Lahar source regions 113 4.4.3 Hazards from pyroclastic density currents 118 4.5 Concluding remarks 120 4.5.1 Further reading 123 REFERENCES 124 APPENDICES 134 Appendix A Grain size distribution and characteristics of the BF2 layer 144 Appendix B Perl code to calculate the horizontal displacement of volcanic particles due to wind advection 144 Appendix C Perl code to assess the uncertainty on the mass and column height using the TEPHRA2 model 150 Appendix D Shape parameters: aspect ration, shape factor and roundness with their 1-sigma standard deviation 158 Appendix E Perl code to calculate the terminal velocity of volcanic particles following the three models described in Chapter 3 158 Appendix F Perl code to calculate the diameter of the equivalent shpere falling at the same terminal velocity than the measured particle 163 ii Appendix G Perl codes to calculate the tephra sedimentation using the model of Bonadonna and Philipps (2003) and the three different approaches discussed in the text in computing the terminal velocity 168 Appendix H Bootstrap with replacement procedure (in Perl) to calculate the recurrence interval (and therefore the probability of an eruption) of a given volcano 181 Appendix I Perl and GMT codes for lahar anaylsis (lahar source region, total volume and potential area of inundation) around Mt. Natib volcano (Bataan Peninsula, Philippines) 187 ABOUT THE AUTHOR End Page iii LIST OF TABLES Table 2.1 Compilation of grain size characteristics for the different technique of TGSD calculations. Data on the 1980 eruption of Mount St. Helens (1980 MSH) are from Durant et al. (2009). 23 Table 2.2 Example of input parameter ranges for the inversion and output example from the inversion. 31 Table 2.3 Output from the inversion on grain size, and the uncertainty analysis. GS: grain size, Ht: column height, DC: Diffusion Coefficient, FTT: Fall Time Threshold. 35 Table 2.4 Input parameters for a forward solution for the BF2 layer using the TEPHRA2 model. See Figure reffig2-1b for abbreviations. 41 Table 3.1 Mean (µ), 1σ standard deviation (Std) and number N of particles ana- lyzed for different shape parameters: aspect ratio (AR), convexity (C), roundness (R) and diameter of the equivalent sphere (ED). GS stands for grain size. 69 Table 4.1 Eruption column height and total mass inputs for deterministic tephra models are based on analog eruptions and Volcano Explosivity Index (VEI). 104 Table 4.2 Tephra fallout thickness (cm) at the BNPP site for each eruption sce- nario in the deterministic analysis. 106 iv LIST OF FIGURES Figure 2.1 (a) Location map of Ecuador, with the main volcanoes (triangles) and localities (circles). Pululagua is located north of Quito and is shown as a big white triangle. The black square around Pululagua represents the area of interest shown in (b) and throughout the different maps in this paper. (b) Region of interest around Pululagua, with the three axes used in this study: 1, the ESE axis in red; 2, the SE axis in blue and 3, the SW axis in green. Numbers refer to sample locations. Cities abbreviations are as follows, A: Atahualpa, C: Calacali, G: Guayllabamba, N: Nanegal, Ng: Nanegalito, No: Nono, P: Perucho, SA: San Antonio, SJM: San Jose de Minas. The dark grey area represents the extent of Quito; (c) Zoom on the Pululagua volcanic complex, showing the irregular-shaped caldera. 10 Figure 2.2 Picture and detailed stratigraphy of the outcrop for three locations at various distances from the vent. (a) Proximal: PL40 located at ≈ 4.5 km southeast from the inferred vent. (b) Medial: PL19 located at ≈ 13 km east-southeast from the inferred vent. (c) Distal: PL24 located at ≈ 21 km southeast from the inferred vent. We defined the inferred vent as being in the center of the caldera, in the current position of the central post-caldera domes.

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