We analyze seismic tremor recorded during eruptive activity over the course of the 2016–2017 eruption of Bogoslof volcano, Alaska. Only regional recordings of the tremor wavefield exist for Bogoslof, making it a challenge to place the recordings in context with other eruptions that are normally captured by local seismic data. We apply a technique of time-frequency polarization analysis to three-component seismic data to reveal the wavefield composition of Bogoslof eruption tremor.We find that at regional distances, the tremor is dominated by P-waves in the band from 1.5 to 10 Hz. Using this information, along with an enriched Bogoslof earthquake catalog, we obtain estimates of average reduced displacement (DR) for eruption tremor during 25 of the 70 Bogoslof events. DR reaches as high as approximately 40 cm2 for two of the major events, similar to other VEI~3 eruptions in Alaska. Overall, average reduced displacement displays a weak correlation to plume height during the first half of the 9-month-long eruption sequence, with a few notable exceptions. The two events with the highest DR values also generated measurable eruption tremor at very-long-periods (VLP) between 0.05 and 0.15 Hz.
This document was originally published in Bulletin of Volcanology by Springer Nature. This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply. doi: 10.1007/s00445-019-1347-0
Haney, Matthew M.; Fee, David; McKee, Kathleen F.; Lyons, John J.; Matoza, Robin S.; Wech, Aaron G.; Tepp, Gabrielle; Searcy, Cheryl; and Mikesell, T. Dylan. (2020). "Co-Eruptive Tremor from Bogoslof Volcano: Seismic Wavefield Composition at Regional Distances". Bulletin of Volcanology, 82(2), 18-1 - 18-14. https://dx.doi.org/10.1007/s00445-019-1347-0