10:15 〜 10:30
[SVC28-06] Integrating remote sensing monitoring and sampling of frequent but small eruptions in Alaska
★Invited Papers
キーワード：tephra, monitoring, geochemistry, lava flows
Syn-eruption documentation of inaccessible eruptions in Alaska relies heavily on remote sensing observations without ground-based geologic data collection to inform eruption monitoring and analysis. However, post-eruption stratigraphically-controlled sampling of these eruptions provides an opportunity to investigate the physical processes driving eruptions and eruptive style. The 2018 eruption of Veniaminof volcano in Alaska resulted in a ~6 x106 m3 basaltic-andesite lava flow bound by an intracaldera ice cap and ~1–2 x106 m3 of proximally deposited tephra. These deposit volumes were tracked via frequent, high-resolution satellite images taken throughout the eruption and aerial structure-from-motion digital elevation models from during and after the end of the eruption. Satellite images also provided constraints on the timing of tephra deposits sampled stratigraphically in a snow pit after the eruption. While compositions did not significantly change over the course of the eruption, we showed that the proportion of tephra with dendritic crystalline tachylyte groundmass increased up to and during a paroxysmal tephra producing event near the end of the eruption. Correlation of groundmass texture with eruptive style during the 2018 eruption provides us with a working hypothesis to test the relationship between tephra componentry and ash productivity in future eruptions. An eruption in spring 2021 already has provided a case study to compare tephra glass composition, grain size, and componentry. In addition, sampling of historical eruptions (1983, 2013, 2018, and 2021) provides a means of tracking variations in the erupted magma composition and monitoring for potential mingling with the more evolved dacitic compositions that last erupted in 800 YBP and could result in a more widespread explosive hazard.