A thermodynamical model for rainfall-triggered volcanic dome collapse

Dome-forming volcanic eruptions typically involve the slow extrusion of viscous lava onto a steep-sided volcano punctuated by collapse and the generation of hazardous pyroclastic flows. We show an unequivocal link between the onset of intense rainfall and lava dome collapse on short time scales (within a few hours) and develop a simple thermodynamical model to explain this behavior. The model is forced with rainfall observations from the Soufriere Hills Volcano, Montserrat, and suggests that when the dome is in a critical state, a minimum rainfall rate of approximately 15 mm hr-1 for 2-3 hr could trigger a dome collapse

Renormalization-Group Study of the Standard Model and its Extensions: The Standard Model

In this paper we present a comprehensive analysis of the running of all the couplings of the standard model to two loops, including threshold effects. Our purpose is twofold—to determine what the running of these parameters may indicate for the physics of the standard model and to provide a template for the study of its extensions up to the Planck mass

Volcanic history, geologic analysis and map of the Prometheus Patera region on Io.

Data from Jupiter's moon Io returned by the Galileo spacecraft have been used to create a geologic map of Prometheus Patera, its associated flow field, and nearby features. We have identified the location of the vent that fed the Prometheus flow field during the Galileo epoch in the north-eastern portion of the main Prometheus flow field. This vent is the probable source of a small sulphur-rich plume. Previous studies suggested that the vent may be atop a tectonic fault but we find that the vent is offset from the putative fault. It is plausible that, in the past, magma exploited the fault to reach the surface at Prometheus Patera, but subsequent magma cooling in the conduit could have caused an obstruction preventing further eruptions from providing significant contributions to the Prometheus flow field. We also speculate on how a new Prometheus plumbing system may be fed by mafic magmas after melt stalls in magma reservoirs during its ascent through the lithosphere from the mantle

Top-Quark and Higgs-Boson Mass Bounds from a Numerical Study of Supersymmetric Grand Unified Theories

We run all the couplings of the minimal supersymmetric (SUSY) extension of the standard model, taking account of the Yukawa sector. After identifying the scale at which the gauge couplings unify, we place bounds on the top-quark mass by requiring equality of the bottom-quark and τ Yukawa couplings at that scale. For MSUSY=1 TeV, Mb=4.6 GeV, we find 139≤Mt≤194 GeV, which remarkably satisfy the ρ-parameter bound. Furthermore, using the minimal SUSY boundary condition on the scalar quartic coupling, we obtain bounds for the mass of the Higgs boson, 44≤MHiggs≤120 GeV

Volcanism in the Solar System.

The myriad bodies that occur in the Solar System have a wide range of properties, from giant gaseous planets such as Jupiter to small, solid, rocky satellites such as our Moon. Exploration by spacecraft during the past four decades has shown that volcanism — an important mechanism by which internal heat is transported to the surface — is common on many of these bodies. There are many common traits; for example, relatively quiet eruptions of molten rock occur on such diverse bodies as the Earth, Mars and Jupiter's moon Io. The volcanic constructs produced, however, vary strikingly, and range from Olympus Mons on Mars, at over 20 km high, to relatively tiny cones on Earth no more than a few tens of metres high. The recognition of icy volcanoes spewing water or organic liquids on some of Saturn's moons constitutes one of the most exciting results to emerge from recent space missions