Abstract
Volcanic explosions release large amounts of hot gas and ash into the atmosphere to form plumes rising several kilometers above eruptive vents, which can pose serious risk on human health and aviation also at several thousands of kilometers from the volcanic source. However the most sophisticate atmospheric models and eruptive plume dynamics require input parameters such as duration of the ejection phase and total mass erupted to constrain the quantity of ash dispersed in the atmosphere and to efficiently evaluate the related hazard. The sudden ejection of this large quantity of ash can perturb the equilibrium of the whole atmosphere triggering oscillations well below the frequencies of acoustic waves, down to much longer periods typical of gravity waves. We show that atmospheric gravity oscillations induced by volcanic eruptions and recorded by pressure sensors can be modeled as a compact source representing the rate of erupted volcanic mass. We demonstrate the feasibility of using gravity waves to derive eruption source parameters such as duration of the injection and total erupted mass with direct application in constraining plume and ash dispersal models.
Highlights
Volcanoes are powerful source of infrasound capable of perturbing the atmosphere well below the frequencies of acoustic waves, down to longer periods typical of gravity waves[1,2,3,4,5,6,7,8,9]
We exploit data collected by four stations at Soufrière Hills Volcano (SHV) to analyze in detail propagation and waveform of gravity waves in the near-source region where distance to the source is smaller than their wavelength[7]
Soufrière Hills Volcano is an andesitic lava dome volcano located at the Northern end of the Lesser Antilles island arc
Summary
Internal Gravity Waves received: 12 May 2016 accepted: 14 October 2016 Published: 10 November 2016. The sudden ejection of this large quantity of ash can perturb the equilibrium of the whole atmosphere triggering oscillations well below the frequencies of acoustic waves, down to much longer periods typical of gravity waves. We demonstrate the feasibility of using gravity waves to derive eruption source parameters such as duration of the injection and total erupted mass with direct application in constraining plume and ash dispersal models. These oscillations were modeled as the response of the atmosphere to either mass or energy injection during the eruption[2,7] Far, such models have only been validated with data recorded at regional or global (i.e. hundreds to thousands of km) distances from the source. Our results suggest that continued observations of large-scale atmospheric perturbations may have future application in assessing the relative magnitude of volcanic explosions and will contribute to improve our knowledge on the input source parameters for accurate ash dispersal models
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