Numerical simulations of the latest caldera-forming eruption of Okmok volcano, Alaska ...
The latest caldera-forming eruption of Okmok volcano, Alaska, had a global atmospheric impact with tephra deposits found in distant Arctic ice cores and a sulfate signal found in Antarctic ice cores. The associated large-scale climate cooling was driven by the amount of sulfur injected into the stra...
| Main Authors: | , , , |
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| Format: | Article in Journal/Newspaper |
| Language: | unknown |
| Published: |
arXiv
2023
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| Subjects: | |
| Online Access: | https://dx.doi.org/10.48550/arxiv.2310.05516 https://arxiv.org/abs/2310.05516 |
| Summary: | The latest caldera-forming eruption of Okmok volcano, Alaska, had a global atmospheric impact with tephra deposits found in distant Arctic ice cores and a sulfate signal found in Antarctic ice cores. The associated large-scale climate cooling was driven by the amount of sulfur injected into the stratosphere during the climactic phase of the eruption. This phase was dominated by pyroclastic density currents, which have complex emplacement dynamics precluding direct estimates of the sulfur stratospheric load. We simulated the dynamics of this climactic phase with the two-phase flow model MFIX-TFM under axisymmetric conditions with several combinations of injection mass flux, emission duration, and topography. Results suggest that a steady mass flux of $8.6-28\times 10^9$ kg/s is consistent with field observations. Stratospheric injections occur in pulses issued from 1) the central plume initially rising above the caldera center, 2) successive co-ignimbrite clouds caused by the encounter of the pyroclastic ... : version submitted to Bulletin of Volcanology, Dec 14, 2022 ... |
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