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Title: InSAR observations of ground deformation : application to the Cascades Volcanic Arc
Author: Parker, Amy L.
ISNI:       0000 0004 5923 7002
Awarding Body: University of Bristol
Current Institution: University of Bristol
Date of Award: 2015
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Interferometric synthetic aperture radar (InSAR) observations of ground deformation play a key role in understanding and monitoring volcanic behaviour throughout the eruption cycle. However, the application of InSAR in volcanic environments remains particularly challenging and better ways of detecting and interpreting commonly observed, low-magnitude deformation signals are required. This thesis approaches this problem in the context of the Cascades Volcanic Arc, where 4 volcanoes are known to have subsided in recent years. Using multi temporal InSAR analysis and large-scale atmospheric models, I develop a new strategy to quantify atmospheric uncertainties a priori for real-time arc-wide volcano monitoring, and improve InSAR measurements at 2 volcanoes in the southern Cascades. At Medicine Lake Volcano, I show that steady subsidence continued at ~10 mm/yr between 2004 - 20 II as recorded since the 1950's. At Lassen Volcanic Center, I carry out the first comprehensive geodetic study and identify subsidence that has decreased in magnitude from >13 mm/yr between 2004 - 2007 to ~8 mm/yr between 2007 - 2010. Long-term volcanic subsidence is a common but poorly understood phenomenon at volcanoes globally. Developing a combined geodetic-thermal model, I present a new way to interpret such deformation signals, and show that cooling and crystallisation of small (<3 km3) magma bodies may result in steady subsidence over decadal time-scales. Applying this model to Medicine Lake Volcano suggests that magma intrusion has occurred more recently than the time of the last eruption ~ 1 ka, and that subsidence may continue for decades. This modelling approach presents a physically reasonable and simple way of coupling geodetic and petrological measurements to provide insight into crustal magma fluxes and the timing of magma intrusion.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available