Modeling Nonlinear Air Waves from Explosive Volcanic Eruptions
Abstract
Explosive volcanic eruptions release large volumes of gas at high pressure, creating waves that propagate nonlinearly near the vent while decaying into ordinary linear infrasound waves. However, nonlinear propagation near the vent is rarely considered in infrasound analyses, and its importance to inferences about infrasound sources is poorly understood. This relatively unknown process may be a major source of error especially in powerful explosive eruptions, in which nonlinear effects are expected to be the strongest. We address this problem with numerical fluid dynamic models of explosions. Numerical modeling allows us to simulate the conditions of a volcanic eruption, predict nonlinear propagation effects, and assess the accuracy of linear infrasound analysis. We investigate a range of realistic eruptive scenarios to determine conditions in which nonlinear effects are significant. We then discuss the implications of these models for infrasound analysis in eruptions, most notably the intense vulcanian eruption of Tungurahua (Ecuador) in July 2013. The results of this project will improve the accuracy of infrasound-based inferences of volcanic processes.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFM.S44A..08A
- Keywords:
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- 7299 General or miscellaneous;
- SEISMOLOGY