Long-period seismicity in the shallow volcanic edifice formed from slow-rupture earthquakes - Université Pierre et Marie Curie Access content directly
Journal Articles Nature Geoscience Year : 2014

Long-period seismicity in the shallow volcanic edifice formed from slow-rupture earthquakes

Abstract

Forecasting of volcanic eruptions is still inadequate, despite technological advances in volcano monitoring. Improved forecasting requires a deeper understanding of when unrest will lead to an actual eruption. Shallow, long-period seismic events often precede volcanic eruptions and are used in forecasting. They are thought to be generated by resonance in fluid-filled cracks or conduits, indicating the presence of near-surface magmatic fluids. Here we analyse very-high-resolution seismic data from three active volcanoes--Mount Etna in Italy, Turrialba Volcano in Costa Rica and Ubinas Volcano in Peru--measured between 2004 and 2009. We find that seismic resonance is dependent on the wave propagation path and that the sources for the long-period seismic waves are composed of short pulses. We use a numerical model to show that slow-rupture failure in unconsolidated volcanic materials can reproduce all key aspects of these observations. Therefore, contrary to current interpretations, we suggest that short-duration long-period events are not direct indicators of fluid presence and migration, but rather are markers of deformation in the upper volcanic edifice. We suggest that long-period volcano seismicity forms part of the spectrum between slow-slip earthquakes and fast dynamic rupture, as has been observed in non-volcanic environments.
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Dates and versions

hal-00932518 , version 1 (27-05-2024)

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Ch. J. Bean, L. de Barros, I. Lokmer, Jean-Philippe Métaxian, G. O'Brien, et al.. Long-period seismicity in the shallow volcanic edifice formed from slow-rupture earthquakes. Nature Geoscience, 2014, 7, pp.71-75. ⟨10.1038/ngeo2027⟩. ⟨hal-00932518⟩
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