Ground-based thermal remote sensing of eruption dynamics at Santiaguito Lava Dome Complex, Guatemala

Here I describe the use of ground-based thermal infrared data to study eruption dynamics associated with the emplacement of an active lava dome at Santiaguito, Guatemala. Integration of thermal data with seismic and infrasound (Chapter 2) allows for detection and determination of explosion frequency (2.3 per hour). It also provides a systematic method to track relative eruption intensity. Explosion source depths are constrained, using the thermo-infrasound delay, to within a 600 in deep region below the vent. Consistent partitioning of released energy into thermal, seismic and infrasound suggests a single source mechanism consistent with shear-induced fragmentation due to intermittent stick-slip of a rising dacite plug.; Integration of thermal data with data regarding the spectral radiance emanating from the vent reveals cyclic temperature fluctuations (Chapter 3). Application of a two-component thermal mixture model to the spectral radiance data reveals a transition from a pre-explosion thermal structure of predominantly cool crust with fractures at near-magmatic temperatures, to a post-explosion isothermal surface. The change in structure is explained in terms of the removal of the chilled crust of lava during explosions to expose a hotter underlying layer.; The use of thermal video camera allows for summit-wide characterization of the vent thermal structure, revealing a structure with an outer ring of high heat and gas permeability surrounding a cooler central region. The outer ring is the source of ash emissions, and the structure is consistent with the at-vent expression of the dacite plug defined in Chapter 2. At the surface this comprises a central plug of, extruding, massive lava, surrounded by a marginal shear zone where heat, gas, and mass can preferentially flow.; Integration of ground and satellite-based (ASTER) thermal data in Chapter 5 allows for estimates of the emplaced block lava flow's dimensions, down-flow heat loss (radiative, convective, conduction, and rainfall evaporation). A total heat flux of 256--913 MW corresponds to an extrusion rate of 0.3--1.2 m3/s.; The results presented in this dissertation demonstrate the utility of ground-based thermal remote sensing to study a wide variety of eruption processes, from deep within the conduit, to the vent, and beyond.