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Abstract Old Faithful Geyser in Yellowstone is one of the most well‐known hydrothermal features in the world. Despite abundant geophysical studies, the structure of Old Faithful's plumbing system beneath ~20‐m depth remained largely elusive. By deploying a temporary dense three‐component geophone array, we observe 1–5 Hz low‐frequency hydrothermal tremor originating from Old Faithful's deeper conduit. By applying seismic interferometry and polarization analyses, we track seismic tremor source migration throughout the eruption/recharge cycle. The tremor source drops rapidly to ~80‐m depth right after the eruption and gradually ascends vertically back to ~20‐m depth, coinciding with the previously inferred bubble trap location. Likely excited by the liquid/steam phase transition, the observed tremor source migration can provide new constraints on the recharge process and deeper conduit geometry. Combined with the shallow conduit structure from previous studies, these results provide constraints on the major fluid pathway down to 80‐m depth.
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This content will become publicly available on December 30, 2025
Volcanic eruption tremor from particle impacts and turbulence using conduit flow models
The intensity of explosive volcanic eruptions is correlated with the amplitude of eruption tremor, a ubiquitously observed seismic signal during eruptions. Here we expand upon a recently introduced theoretical model that attributes eruption tremor to particle impacts and dynamic pressure changes in the turbulent flow above fragmentation (Gestrich et al., 2020). We replace their point source model with Rayleigh wave Green's functions with full Green's functions and account for depth variation of input fields using conduit flow models. The latter self-consistently capture covariation of input fields like particle velocity, particle volume fraction, and density. Body wave contributions become significant above 2-3 Hz, bringing the power spectral density (PSD) closer to observations. Conditions at the vent are not representative of flow throughout the tremor source region and using these values overestimates tremor amplitude. Particle size and its depth distribution alter the PSD and where dominant source contributions arise within the conduit. Solutions with decreasing mass eruption rate, representing a waning eruption, reveal a shift in the dominant tremor contribution from turbulence to particle impacts. Our work demonstrates the ability to integrate conduit flow modeling with volcano seismology studies of eruption tremor, providing an opportunity to link observations to eruptive processes.
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- PAR ID:
- 10594468
- Publisher / Repository:
- Seismica
- Date Published:
- Journal Name:
- Seismica
- Volume:
- 4
- Issue:
- 1
- ISSN:
- 2816-9387
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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