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Relaxation time spectra of basaltic lavas between 500–1150°C reveal patterns of Kramers–Kronig inconsistency of the complex viscoelastic shear modulus

In: Contributions to Geophysics and Geodesy, vol. 49, no. 2
Martin Bednárik - Igor Kohút

Details:

Year, pages: 2019, 109 - 132
Language: eng
Keywords:
viscoelasticity, generalized Maxwell body, Kramers–Kronig relationships, relaxation time spectrum, viscoelastic modulus inconsistency
About article:
An important, yet until now neglected, aspect of the viscoelastic behaviour of lavas is the Kramers–Kronig consistency of their complex viscoelastic shear modulus. The most general linear viscoelastic model – the generalized Maxwell body with continuous relaxation time spectrum – produces a consistent storage and loss modulus, as can be verified by Kramers–Kronig formulae. We reprocessed the original datasets of the high-precision laboratory data by James et al. (2004) supplied as pairs of magnitude of the complex viscoelastic shear modulus and the loss angle. We introduce the magnitude-borne and loss-angle-borne logarithmic relaxation time spectra and their ratio as a suitable indicator of the linear viscoelastic inconsistency. The basaltic lavas from Etna, Hawai'i and Vesuvius have shown a general convergence to the ideal consistency with increasing temperature, although each sample with an individual inconsistency pattern. The biggest surprise is the inconsistency ratio rising to ∼20 in Etna 1992 top sample at 786°C. Such a high inconsistency level still waits for an explanation and for the discoveries of its class-mates either in laboratory or field experiments.

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How to cite:
ISO 690:
Bednárik, M., Kohút, I. 2019. Relaxation time spectra of basaltic lavas between 500–1150°C reveal patterns of Kramers–Kronig inconsistency of the complex viscoelastic shear modulus. In Contributions to Geophysics and Geodesy, vol. 49, no.2, pp. 109-132. 1338-0540. DOI: https://doi.org/10.2478/congeo-2019-0006

APA:
Bednárik, M., Kohút, I. (2019). Relaxation time spectra of basaltic lavas between 500–1150°C reveal patterns of Kramers–Kronig inconsistency of the complex viscoelastic shear modulus. Contributions to Geophysics and Geodesy, 49(2), 109-132. 1338-0540. DOI: https://doi.org/10.2478/congeo-2019-0006
About edition:
Published: 30. 6. 2019