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Unraveling Pavlof Volcano\'s Shallow Plumbing System: Insights from Seismoacoustic and Multidisciplinary Analyses

Darren Tan 1, David Fee1, Vanesa Burgos1, Taryn Lopez1, Matt Haney2, Chris Waythomas2, Stephen McNutt3, Társilo Girona1, Pavel Izbekov1, Jessica Larsen1, Valerie Wasser1, Tara Shreve4, Jamshid Moshrefzadeh5, Ronni Grapenthin1, Mario Angarita1, Pablo Saunders-Shultz2

  • Affiliations: 1Alaska Volcano Observatory, Geophysical Institute, University of Alaska Fairbanks, AK, USA; 2U.S. Geological Survey, Alaska Volcano Observatory, Anchorage, AK, USA; 3University of South Florida, School of Geosciences, Tampa, FL, USA; 4Geologic Hazards Program, Utah Geological Survey, Salt Lake City, UT, USA; 5Alaska Division of Geological and Geophysical Surveys, Fairbanks, AK, USA

  • Presentation type: Talk

  • Presentation time: Friday 15:00 - 15:15, Room R280

  • Programme No: 1.5.4

  • Theme 1 > Session 5

Abstract

Pavlof Volcano, a frequently active volcano in the Aleutian arc, has erupted six times within the past two decades (2007, 2013, 2014, 2016, 2021--22). Many Pavlof Volcano eruptions lack precursory seismicity or detectable ground deformation, making them challenging to forecast. Since 2007, these eruptions have ranged from Strombolian to sub-Plinian (VEI 2--3), with their characteristics seemingly related to their active vent location, which switches between the southeast flank and summit crater. To better understand Pavlof Volcano's plumbing system and improve eruption forecasts, we integrate geophysical, petrologic, gas, and satellite-based thermal infrared data to conduct a multidisciplinary synthesis of its past six eruptions. Notably, our newly developed tremor detection model, the VOlcano Infrasound and Seismic Spectrogram Network (VOISS-Net), reveals unique pre- and co-eruptive seismic tremor regimes associated with each vent system. Local infrasound data and air-to-ground coupled waves used to refine explosion catalogs also uncover evidence of gas-rich explosions from the summit vent previously thought to be inactive during the 2021--22 eruption. Whole-rock composition and ash analyses indicate a near-uniform basaltic andesite composition spanning multiple eruptions, and a consistent anomalous presence of decayed olivines in erupted material. These findings lead us to propose a new conceptual model for Pavlof Volcano's plumbing system: a shallow T-junction outlet controlling seismic tremor diversity and the partitioning of gas-charged magma, and an elongated, heated conduit transporting magma from depth and facilitating solid-state diffusion of recycled magma between eruptions. We suggest magma ascent rate and conduit plugging modulate the eruption styles seen at Pavlof Volcano.