Strombolian activity is characterized by repeated, low energy, explosions and is named after the volcano where such activity has persisted for around 2000 years, i.e., Stromboli (Aeolian Islands, Italy). Stromboli represents an excellent laboratory where measurements of such explosions can be made from safe, but close, distances. During a field campaign in 2008, two 15 cm diameter bombs were quenched and collected shortly after a normal explosion. The bombs were characterized in terms of their textural, chemical, rheological, and geophysical signatures. The vesicle and crystal size distribution of the samples, coupled with the glass chemistry, enabled us to quantify variations in the degassing history and rheology of the magma resident in the shallow (i.e., in last 250 m of conduit length). The different textural facies observed in these bombs showed that fresh magma was mingled with batches of partially to completely degassed, oxidized, high-crystallinity, high-viscosity, evolved magma. This magma sat at the top of the conduit and played only a passive role in the explosive process. The fresh, microlite-poor, vesiculated batch, however, experienced a response to the explosive event, by undergoing rapid decompression. Integration of geophysical measurements with sample analyses indicates that popular bubble-bursting models may not fit this case. We suggest that the degassed, magma forms a plug, or rheological layer, at the top of the conduit, through which the fresh magma bursts. In this model we need to consider the paradox of a slug ascending too fast through a magma of varying viscosity and yield strength.

We provide measurements of thermal diffusivity (D), heat capacity (C P), and viscosity () for 12 remelted natural lavas and 4 synthetic glasses and melts, ranging in composition from leucogranite to low-silica basalt, and calculate their thermal conductivity (k). Both viscosity and the glass transition temperature decrease with decreasing melt polymerization. For basaltic glasses, D is low, ~0.5 mm 2 s-1 at room temperature, decreases slightly with increasing temperature, and then drops upon melting to ~0.25 to 0.35 mm 2 s-1. Other samples behave similarly. Despite scatter, clear correlations exist between D of glass or melt with Si content, density, NBO/T, and, most strongly, with fragility (m). Glass thermal diffusivity is represented by D = FT-G +HT, where F, G and H are fitting parameters. For melts, ∂D/∂T was resolved only for dacite-andesite and MORB: a positive slope is consistent with other iron-bearing samples. Glass and liquid C P depend on density and other physical properties, but not exactly in the same manner as D.. We calculate thermal conductivity (k) from these data and demonstrate that k for glasses is described by a Maier-Kelly formula. Large scatter exists for k at 298 K, but silicic to intermediate melts have k between 1.8 and 1.3 Wm-1 K-1 , whereas basaltic melts are constrained to ~1.4 ± 0.1 Wm-1 k-1. Low values for thermal diffusivity and viscosity for basaltic melts suggests that basalts transfer heat much more efficiently by advection than by conduction alone, and that partially molten zones in the mantle quickly become more thermally insulating than non-molten zones, potentially contributing to melt localization during decompression melting.

ACKNOWLEDGEMENTSThis work could not have been completed without the generous help of a number of people who I am very thankful for. Firstly, I must thank my advisor, Dr. Alan Whittington, for taking me on an epic adventure over not just the duration of graduate school, but during my undergraduate years as well. Through his patience and guidance, I have grown into the professional that I am today. I must also thank Dr. Kevin Shelton, and Dr. Stephen Lombardo, for providing their time and participating on my thesis committee. I next need to thank my fellow lab mates and field researchers, Alexander Sehlke and Geneviéve Robert. Thank you both for your tireless help in the lab, and for helping to keep me sane over the years. I would also like to thank the National Science Foundation for funding this project, and providing me with the opportunity to explore science in the field and laboratory. Thank the University of Missouri Geology department and alumni for providing generous scholarships over the years, which I am thankful to have received. I would also like to thank all of the faculty and professors I have worked with over the years, for which I am very grateful for all the time we have shared together and for all I have learned from you. Thanks to INSIVUMEH and resident researchers and scientists of Guatemala, namely, Don Eddy, Gustavo Chigna, and our trusted guide José.Last but, certainly not least, I need to thank my friends and family. Thanks to Elizabeth Gammel, who has endured my ramblings, singing, and dancing, while being the best study buddy I could ask for. Thanks to my mother, father, step-parents, and grandmother for providing me with the support and guidance I needed so dearly. Thanks to my sister for being the smarter sibling and causing me to always try harder. Finally, thanks to my best friend, girlfriend, and roommate, for loving me unconditionally through the roller coaster of graduate school, I couldn't have done this without you.

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