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Seismo-acoustic monitoring of experimental volcanic fragmentation, fluid-filled cavities and mass flux dynamics

Alejandra Arciniega-Ceballos 1, Miguel A Alatorre-Ibargüengoitia2, Bettina Scheu3, Gerardo M Mendo-Pérez4, Donald B Dingwell3

  • Affiliations: 1Instituto de Geofísica, Departamento de Vulcanología, UNAM, Mexico. 2Centro de Investigación en Gestión de Riesgos y Cambio Climático, UACH, Tuxtla Gutiérrez, Mexico. 3Department of Earth and Environmental Sciences, Munich, Germany. 4ERI, University of Tokyo, Tokyo, Japan.

  • Presentation type: Poster

  • Presentation time: Tuesday 16:30 - 18:30, Room Poster Hall

  • Poster Board Number: 88

  • Programme No: 3.16.15

  • Theme 3 > Session 16

Abstract

We performed experiments in a shock-tube apparatus that combined direct observations of rock fragmentation and mass flux dynamics, with a time series parameterization of pressure, elasto-acoustic signals and conduit elastic deformation. These combined observations show that the style of rock fragmentation processes, triggered by rapid decompression, determines the style of conduit dynamics and mass flux behavior. Here, we present visual evidence of the formation and resonance of fluid-filled cavities, and analyze the frequency characteristics and waveforms of the elasto-acoustic signals associated with the dynamics of gas-particle-filled cracks. Our findings indicate that the gas-particle mixtures within cavities transit up and down causing erosion and/or accretion in the lower and upper surfaces that confine each cavity. This behavior induces striking signals with harmonic characteristics that attenuate with time. The distribution of an assembly of cavities determines the architecture of the conduit and modifies the frequency content of the signals. We  calculate the crack stiffness curves and the impedance contrast and the resonance modes for the experimental cracks based on the fluid-driven crack model.The spectral characteristics of the experimental signals fit the fluid-filled crack model confirming that the crack model is useful to interpret resonant modes at different scales. The present observations represent a major contribution that help to clarify the source mechanism of signals related to fluid-filled cavities as can be the LP and VLP signals observed in many active volcanoes around the world.