Constraints on magma storage conditions based on geodetic volume change and erupted magma volume and application to the 2011 and 2018 eruptions at Kirishima Shinmoe-dake volcano, Japan

Abstract We investigated magma storage conditions prior to the 2011 and 2018 eruptions at Kirishima Shinmoe-dake volcano in Japan based on the relationship between geodetic volume change of magma chamber and erupted magma volume. We derived an analytical expression for the ratio of the erupted magma volume to the geodetic volume change (“volume ratio”), which was formulated as a function of parameters related to the magma storage conditions. This expression shows that the volume ratio is strongly dependent on the effective compressibility of the magma chamber, which in turn depends on the rigidity of surrounding host rocks and shape of the chamber. For the Shinmoe-dake eruptions, the magnitude of the volume change (i.e., deflation) of a spherical magma chamber associated with lava effusion was estimated based on geodetic observations. The erupted magma volume was estimated from a SAR image analysis of the lava accumulation inside the summit crater. Based on these observations, we estimated that the volume ratio in 2011 and 2018 was 2.69 and 2.33, respectively. Substituting the estimated volume ratio into the analytical expression revealed that the observed geodetic data and volume ratio can be explained only when the magma chamber, which was assumed to be spherical, is filled with bubble-free magma. This result suggests that efficient gas segregation from the chamber occurred prior to the eruptions. Our results indicate that combining multi-observation data based on the volume ratio provides valuable information about the magma storage process, such as the behavior of the gas phase in the magma chamber. Graphical Abstrac

Targeted disruption of AdipoR1 and AdipoR2 causes abrogation of adiponectin binding and metabolic actions.

Adiponectin plays a central role as an antidiabetic and antiatherogenic adipokine. AdipoR1 and AdipoR2 serve as receptors for adiponectin in vitro, and their reduction in obesity seems to be correlated with reduced adiponectin sensitivity. Here we show that adenovirus-mediated expression of AdipoR1 and R2 in the liver of Lepr(-/-) mice increased AMP-activated protein kinase (AMPK) activation and peroxisome proliferator-activated receptor (PPAR)-alpha signaling pathways, respectively. Activation of AMPK reduced gluconeogenesis, whereas expression of the receptors in both cases increased fatty acid oxidation and lead to an amelioration of diabetes. Alternatively, targeted disruption of AdipoR1 resulted in the abrogation of adiponectin-induced AMPK activation, whereas that of AdipoR2 resulted in decreased activity of PPAR-alpha signaling pathways. Simultaneous disruption of both AdipoR1 and R2 abolished adiponectin binding and actions, resulting in increased tissue triglyceride content, inflammation and oxidative stress, and thus leading to insulin resistance and marked glucose intolerance. Therefore, AdipoR1 and R2 serve as the predominant receptors for adiponectin in vivo and play important roles in the regulation of glucose and lipid metabolism, inflammation and oxidative stress in vivo