Jones Meghan

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  • Article
    The largest deep-ocean silicic volcanic eruption of the past century
    (American Association for the Advancement of Science, 2018-01-10) Carey, Rebecca ; Soule, Samuel A. ; Manga, Michael ; White, James D. L. ; McPhie, Jocelyn ; Wysoczanski, Richard ; Jutzeler, Martin ; Tani, Kenichiro ; Yoerger, Dana R. ; Fornari, Daniel J. ; Caratori Tontini, Fabio ; Houghton, Bruce ; Mitchell, Samuel ; Ikegami, Fumihiko ; Conway, Chris E. ; Murch, Arran ; Fauria, Kristen ; Jones, Meghan ; Cahalan, Ryan ; McKenzie, Warren
    The 2012 submarine eruption of Havre volcano in the Kermadec arc, New Zealand, is the largest deep-ocean eruption in history and one of very few recorded submarine eruptions involving rhyolite magma. It was recognized from a gigantic 400-km2 pumice raft seen in satellite imagery, but the complexity of this event was concealed beneath the sea surface. Mapping, observations, and sampling by submersibles have provided an exceptionally high fidelity record of the seafloor products, which included lava sourced from 14 vents at water depths of 900 to 1220 m, and fragmental deposits including giant pumice clasts up to 9 m in diameter. Most (>75%) of the total erupted volume was partitioned into the pumice raft and transported far from the volcano. The geological record on submarine volcanic edifices in volcanic arcs does not faithfully archive eruption size or magma production.
  • Article
    On the mechanical effects of poroelastic crystal mush in classical magma chamber models
    (American Geophysical Union, 2018-09-30) Liao, Yang ; Soule, S. Adam ; Jones, Meghan
    Improved constraints on the mechanical behavior of magma chambers is essential for understanding volcanic processes; however, the role of crystal mush on the mechanical evolution of magma chambers has not yet been systematically studied. Existing magma chamber models typically consider magma chambers to be isolated melt bodies surrounded by elastic crust. In this study, we develop a physical model to account for the presence and properties of crystal mush in magma chambers and investigate its impact on the mechanical processes during and after injection of new magma. Our model assumes the magma chamber to be a spherical body consisting of a liquid core of fluid magma within a shell of crystal mush that behaves primarily as a poroelastic material. We investigate the characteristics of time‐dependent evolution in the magma chamber, both during and after the injection, and find that quantities such as overpressure and tensile stress continue to evolve after the injection has stopped, a feature that is absent in elastic (mushless) models. The time scales relevant to the postinjection evolution vary from hours to thousands of years, depending on the micromechanical properties of the mush, the viscosity of magma, and chamber size. We compare our poroelastic results to the behavior of a magma chamber with an effectively viscoelastic shell and find that only the poroelastic model displays a time scale dependence on the size of the chamber for any fixed mush volume fraction. This study demonstrates that crystal mush can significantly influence the mechanical behaviors of crustal magmatic reservoirs.