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

The PIs will improve the ability to detect precursory activity leading to active volcanism at both Okmok caldera and Redoubt volcano, Alaska, as well as increase understanding of the complexity of magma storage at Redoubt. They will investigate important questions at Redoubt regarding (1) the spatial extent of the magma chamber, (2) if magma migrates from a primary magma chamber to a second magma reservoir located somewhere between 2 and 4.5 km depth, (3) if temporary perturbations to the upper crustal velocity structure of Redoubt, reflecting CO2 degassed at mid-crustal depths, can be observed, possibly as early as several months prior to the 2009 event, thus serving as an early indicator of the eruption. At Okmok, they will examine important questions including (1) the existence of early signs of volcanic unrest preceding the 2008 eruption and/or (2) early indicators that the eruption would emanate NW of Cone D instead of an expected eruption at Cone A, (3) if there were indications of shallow magma movement (1-3 km depth) within the caldera in the months leading up to the 2008 eruption. One promising approach to improve detection of precursory activity leading to active volcanism at Okmok and Redoubt is to carry out seismic interferometry using ambient noise recorded at these volcanoes (specifically pre- through post-eruption for the 2008 Okmok and 2009 Redoubt eruptions). Okmok and Redoubt are two of the most active volcanoes in the Aleutian Arc and, as such, pose major hazards to people living within these regions, air traffic, local fisheries, and local oil production facilities. This study will improve our ability to detect precursory activity leading to active volcanism at both Okmok and Redoubt as well as increase our understanding of the complexity of magma storage at Redoubt. The study will also broaden the experience of an early career female scientist. Bennington, N. L., Haney, M., De Angelis, S., Thurber, C. H., & Freymueller, J.. "Monitoring changes in seismic velocity related to an ongoing rapid inflation event at Okmok volcano," Journal of Geophysical Research: Solid Earth, v.120, 2015, p. 5664. doi:10.1002/2015JB011939