Modeling long-term volcanic deformation at Kusatsu-Shirane and Asama volcanoes, Japan, using the GNSS coordinate time series

Long-term deformation of Kusatsu-Shirane and Asama volcanoes in central Japan were investigated using Global Navigation Satellite System (GNSS) measurements. Large postseismic deformation caused by the 2011 Tohoku earthquake—which obscures the long-term volcanic deformation—was effectively removed by approximating the postseismic and other recent tectonic deformation in terms of quadrature of the geographical eastings/northings. Subsequently, deformation source parameters were estimated by the Markov Chain Monte Carlo (MCMC) method and linear inversion, employing an analytical model that calculates the deformation from an arbitrary oriented prolate/oblate spheroid. The deformation source of Kusatsu-Shirane volcano was found to be a sill-like oblate spheroid located a few kilometers northwest of the Yugama crater at a depth of approximately 4 $$\text {km}$$ km , while that of Asama was also estimated to be a sill-like oblate spheroid beneath the western flank of the edifice at a depth of approximately 12 $$\text {km}$$ km , along with the previously reported shallow east–west striking dike at a depth of approximately 1 $$\text {km}$$ km . It was revealed that (1) volume changes of the Kusatsu-Shirane deformation source and the shallow deformation source of Asama were correlated with the volcanic activities of the corresponding volcanoes, and (2) the Asama deep source has been steadily losing volume, which may indicate that the volcano will experience fewer eruptions in the near future.

Modeling long-term volcanic deformations at the Kusatsu-Shirane and Asama volcanoes, Japan using the GNSS coordinate time series

Long-term deformations of the Kusatsu-Shirane and Asama volcanoes in central Japan were investigated using Global Navigation Satellite System (GNSS) measurements. Large postseismic deformations caused by the 2011 Tohoku earthquake — which obscure the long-term volcanic deformations — were effectively removed by approximating the postseismic and other recent tectonic deformations in terms of quadrature of the geographical eastings/northings. Subsequently, deformation source parameters were estimated by the Markov Chain Monte-Carlo (MCMC) method and linear inversion. The deformation source of the Kusatsu-Shirane volcano was found to be a sill-like oblate spheroid located a few kilometers northwest of the Yugama crater at a depth of approximately five km, while that of Asama was also estimated to be a sill-like oblate spheroid located at the western flank of the edifice at a depth of approximately 13 km, along with the previously reported shallow east-west striking dike at a depth of approximately 1 km. It was revealed that 1) volume changes of the Kusatsu-Shirane deformation source and the shallow deformation source of Asama were correlated with the volcanic activities of the corresponding volcanoes, and 2) the Asama deep source has been steadily losing volume, which may indicate that the volcano will experience less eruptions in the near future.

Dynamics of Aqueous “Liquid Marbles” in Three Dimensional Biphasic Systems

Liquid marbles are defined as hydrophilic liquid droplets that are coated with hydrophobic powdered materials. Till now, the behaviour of liquid marbles has been studied for triphasic systems comprising of the constituent hydrophilic phase, the hydrophobic coating and ambient air. In this article, we report the dynamics of aqueous droplets of varying pH (i.e. acidic, neutral and basic, respectively) moving under the influence of gravity in commonly available mustard oil. We find that the said dynamics could be divided into four parts: (i) formation of hanging aqueous droplets from the top surface of oil, (ii) oblate spheroid droplets moving at constant velocity due to viscous drag, (iii) distant repulsive interactions between two droplets due to “reverse Cheerios effect” and (iv) final impact between the two droplets explained by viscoelastic sliding friction over a compliant surface. This work would be of great interest to researchers working in the domain of interfacial phenomena like oil exploration, biomedical engineering, food technology and towards the realization of droplet-based microfluidic computational platforms for “more than Moore’s” paradigm in the domain of unconventional computation.

Pattern formation on a growing oblate spheroid. an application to adult sea urchin development

<p style='text-indent:20px;'>In this study, the formation of the adult sea urchin shape is rationalized within the Turing's theory paradigm. The emergence of protrusions from the expanding underlying surface is described through a reaction-diffusion model with Gray-Scott kinetics on a growing oblate spheroid. The case of slow exponential isotropic growth is considered. The model is first studied in terms of the spatially homogenous equilibria and of the bifurcations involved. Turing diffusion-driven instability is shown to occur and the impact of the slow exponential growth on the resulting Turing regions adequately discussed. Numerical investigations validate the theoretical results showing that the combination between an inhibitor and an activator can result in a distribution of spot concentrations that underlies the development of ambulacral tentacles in the sea urchin's adult stage. Our findings pave the way for a model-driven experimentation that could improve the current biological understanding of the gene control networks involved in patterning.</p>

Analytical and numerical methods of converting Cartesian to ellipsoidal coordinates

In this work, two analytical and two numerical methods of converting Cartesian to ellipsoidal coordinates of a point in space are presented. After slightly modifying a well-known exact analytical method, a new exact analytical method is developed. Also, two well-known numerical methods, which were developed for points exactly on the surface of a triaxial ellipsoid, are generalized for points in space. The four methods are validated with numerical experiments using an extensive set of points for the case of the Earth. Then, a theoretical and a numerical comparative assessment of the four methods is made. Furthermore, the new exact analytical method is applied for an almost oblate spheroid and for the case of the Moon and the results are compared. We conclude that, the generalized Panou and Korakitis’ numerical method, starting with approximate values from the new exact analytical method, is the best choice in terms of accuracy of the resulting ellipsoidal coordinates.