Relative velocity changes using ambient seismic noise at Okmok and Redoubt volcanoes, Alaska

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The PIs will improve the ability to detect precursory activity leading to activevolcanism at both Okmok caldera and Redoubt volcano, Alaska, as well as increase understanding ofthe complexity of magma storage at Redoubt. They will investigate important questions at Redoubtregarding (1) the spatial extent of the magma chamber, (2) if magma migrates from a primary magmachamber to a second magma reservoir located somewhere between 2 and 4.5 km depth, (3) if temporaryperturbations to the upper crustal velocity structure of Redoubt, reflecting CO2 degassed at mid-crustaldepths, can be observed, possibly as early as several months prior to the 2009 event, thus serving as anearly indicator of the eruption. At Okmok, they will examine important questions including (1) theexistence of early signs of volcanic unrest preceding the 2008 eruption and/or (2) early indicators that theeruption would emanate NW of Cone D instead of an expected eruption at Cone A, (3) if there wereindications of shallow magma movement (1-3 km depth) within the caldera in the months leading up tothe 2008 eruption. One promising approach to improve detection of precursory activity leading to activevolcanism at Okmok and Redoubt is to carry out seismic interferometry using ambient noise recorded atthese volcanoes (specifically pre- through post-eruption for the 2008 Okmok and 2009 Redoubteruptions).Okmok and Redoubt are two of the most active volcanoes in the Aleutian Arc and, assuch, pose major hazards to people living within these regions, air traffic, local fisheries, and local oilproduction facilities. This study will improve our ability to detect precursory activity leading to activevolcanism at both Okmok and Redoubt as well as increase our understanding of the complexity of magmastorage at Redoubt. The proposed study will also broaden the experience of an early career femalescientist.