@article{fdi:010085259,
  title = {{A} data-based minimal model of episodic inflation events at volcanoes},
  author = {{W}alwer, {D}. and {G}hil, {M}. and {C}alais, {E}ric},
  editor = {},
  language = {{ENG}},
  abstract = {{S}pace geodetic time series, be they ground-based or space-based, have increased in length and accuracy. {T}hese series can now be mined for information on the qualitative dynamics of volcanic systems directly from surface deformation data. {H}ere, we study three volcanoes: {A}kutan and {O}kmok that are part of the {A}leutian arc, and {P}iton de la {F}ournaise on la {R}eunion {I}sland. {A}ll three are continuously monitored by the {G}lobal {P}ositioning {S}ystem ({GPS}) and exhibit common stair step-shaped inflation cycles sometimes referred to as to as "episodic inflation events". {H}ere we seek to characterize the corresponding dynamical regime of pressure build-up within their plumbing system. {T}o do so, we make use of {M}ultichannel {S}ingular {S}pectrum {A}nalysis ({M}-{SSA}), a data-adaptive, non-parametric time series analysis methodology that allows for 1) the reliable detection and extraction of such patterns even when the corresponding signal lies close to, or even below, the data scatter; and 2) the extraction of information relevant to the underlying qualitative dynamics without a priori assumptions on the underlying physical mechanisms. {F}or our three volcanoes, we find that the inflation cycles resemble the relaxation oscillations of a simple oscillator that involves a nonlinear dissipative mechanism. {T}his finding provides important guidelines for physics-based models of episodic inflation cycles. {I}n fact, the three volcanoes share a plumbing system composed of several interconnected storage bodies. {G}uided by the qualitative {M}-{SSA}-inferred dynamics, we formulate a simple physical model of two magma bodies connected by a conduit in which the viscosity of the fluid varies with temperature or magma crystallization. {W}e show that such a model possesses internal relaxation oscillations similar to those of a simple oscillator. {T}hese oscillations correspond to repetitive events with sharp variations in the rate of magma transport and they can account for episodic events of pressure build-up in magma bodies, with no need for a time-dependent magma flux into or out of the system. {W}e also show that the model's number of degrees of freedom is consistent with the amount of information extracted from {M}-{SSA} data analysis. {T}he approach presented here relies on the robust statistical analysis of deformation time series to constrain the phenomenology of pressure build-up within a volcanic plumbing system; it provides a novel framework for understanding the dynamics of volcanic systems.},
  keywords = {episodic inflation events ; relaxation oscillations ; statistical analysis of time series ; magma transport ; {H}opf bifurcation ; {REUNION} ; {ALASKA} ; {AKUTAN} {VOLCAN} ; {OKMOK} {VOLCAN} ; {PITON} {DE} {LA} {FOURNAISE}},
  booktitle = {},
  journal = {{F}rontiers in {E}arth {S}cience},
  volume = {10},
  numero = {},
  pages = {759475 [18 p.]},
  year = {2022},
  DOI = {10.3389/feart.2022.759475},
  URL = {https://www.documentation.ird.fr/hor/fdi:010085259},
}