Magma wagging and whirling : excitation by gas flux
MetadataShow full item record
Gas flux in volcanic conduits is often associated with long-period oscillations known as seismic tremor (Lesage et al.; Nadeau et al.). In this study, we revisit and extend the ‘magma wagging’and ‘whirling’models for seismic tremor, in order to explore the effects of gas flux on the motion of a magma column surrounded by a permeable vesicular annulus (Jellinek & Bercovici; Bercovici et al.; Liao et al.). We find that gas flux flowing through the annulus leads to a Bernoulli effect, which causes waves on the magma column to become unstable and grow. Specifically, the Bernoulli effects are associated with torques and forces acting on the magma column, increasing its angular momentum and energy. As the displacement of the magma column becomes large due to the Bernoulli effect, frictional drag on the conduit wall decelerates the motions of the column, restoring them to small amplitude. Together, the Bernoulli effect and the damping effect contribute to a self-sustained wagging-and-whirling mechanism that help explain the longevity of long-period seismic tremor.
Author Posting. © The Authors, 2018. This article is posted here by permission of The Royal Astronomical Society for personal use, not for redistribution. The definitive version was published in Geophysical Journal International 215 (2018): 713–735, doi:10.1093/gji/ggy313.
Suggested CitationArticle: Liao, Yang, Bercovici, David, "Magma wagging and whirling : excitation by gas flux", Geophysical Journal International 215 (2018): 713–735, DOI:10.1093/gji/ggy313, https://hdl.handle.net/1912/10696
Showing items related by title, author, creator and subject.
The influence of magma supply and eruptive processes on axial morphology, crustal construction and magma chambers Hooft, Emilie E. E. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1996-12)Two-thirds of the surface of the Earth is created at mid-ocean ridges where magmas rise from the mantle and cool to form the oceanic crust. The objective of this Thesis is to examine the influence of magma supply and ...
Ciazela, Jakub; Dick, Henry J. B.; Koepke, Juergen; Pieterek, Bartosz; Muszynski, Andrzej; Botcharnikov, Roman; Kuhn, Thomas (2017-07)Gabbroic veins enclosed in mantle peridotite from ocean core complexes next to oceanic transform faults demonstrate sub-crustal crystallization of silicate minerals from a MORB-like melt. Cooler lithosphere there may ...
Canales, J. Pablo; Dunn, Robert A.; Arai, Ryuta; Sohn, Robert A. (2017-01)Hydrothermal circulation at mid-ocean ridge volcanic segments extracts heat from crustal magma bodies. However, the heat source driving hydrothermal circulation in ultramafic outcrops, where mantle rocks are exhumed in ...