In the framework of the rigorous fusion of GNSS and InSAR observations, the presented work carries out at a straightforward comparison of the wet delay, caused by water vapor, derived from GNSS and InSAR. The contributions of the two sensors to the wet delay are compared in the line of sight towards the SAR satellite. Comparisons of GNSS observations with the satellite-directed InSAR data show that only a partial component of the wet delay remains after the interferogram formation.
This doctoral thesis applies measurements of ground deformation from satellite radar using their potential to play a key role in understanding volcanic and magmatic processes throughout the eruption cycle. However, making these measurements is often problematic, and the processes driving ground deformation are commonly poorly understood. These problems are approached in this thesis in the context of the Cascades Volcanic Arc. From a technical perspective, the thesis develops a new way of using regional-scale weather models to assess a priori the influence of atmospheric uncertainties on satellite measurements of volcano deformation, providing key parameters for volcano monitoring. Next, it presents detailed geodetic studies of two volcanoes in northern California: Medicine Lake Volcano and Lassen Volcanic Centre. Finally, the thesis combines geodetic constraints with petrological inputs to develop a thermal model of cooling magma intrusions. The novelty and range of topics covered in this thesis mean that it is a seminal work in volcanic and magmatic studies.
Interferometric synthetic aperture radar (InSAR) is a relatively new remote sensing tool that is capable of measuring ground-surface deformation with centimeter-to-subcentimeter precision at a spatial resolution of tens of meters over an area of hundreds to thousands of square kilometers. With its global coverage and all-weather imaging capability, InSAR has become an increasingly important technique for studying volcanoes in remote regions such as the Aleutian Islands. The spatial distribution of surface deformation data derived from InSAR images enables the construction of detailed mechanical models to enhance the study of magmatic processes. InSAR Imaging of Aleutian Volcanoes: • Provides a theoretical framework for InSAR observations and capabilities • Discusses state-of-the-art InSAR analysis techniques • Describes the structure, eruptive history, and magma composition of volcanoes along the entire Aleutian arc • Presents conceptual models for the magma plumbing systems of Aleutian volcanoes based on InSAR results combined with geophysical, geological and geochemical observations. • Synthesizes observations of deformation along the Aleutian arc and compares those results to other active arcs around the world. • Is illustrated throughout with high-resolution color satellite radar images
This 43-page report presents new Interferometric Synthetic Aperture Radar (InSAR) analysis of ground water subsidence in Cedar Valley in Iron County, Utah. This analysis is based on InSAR data from the ERS-1/2 satellites from 1992 to 2000, and the Envisat satellite from 2004 to 2010. A stack of five consecutive interferograms from the 1992-2000 time period and a stack of four consecutive interferograms from the 2004-2010 time period are included in this report; however, decorrelation in the vicinity of the Enoch graben makes an estimate of total deformation impossible using the stacks. In total, surface deformation has impacted approximately 256 km² (100 mi²) in Cedar Valley. Subsidence rates in the vicinity of the Enoch graben increased from approximately 0.5-1.0 cm/yr to roughly 1-2 cm/yr after 1999. Similarly, rates in central Cedar Valley show a general increasing trend after 1999, but rates appear to be more erratic than the other two sites. The spatial distribution of deformation in Cedar Valley correlates well with both the location of observed fissuring as well as the location of both municipal and private groundwater production wells. The fissuring observed near Quichapa Lake, as well as within the Enoch graben, is likely a direct result of groundwater pumping in these areas.
