Products of voluminous pyroclastic eruptions with eruptive draw-down of several kilometers provide a snap-shot view of batholith-scale magma chambers, and quench pre-eruptive isotopic fractionations (i.e., temperatures) between minerals. We report analyses of oxygen isotope ratio in individual quartz phenocrysts and concentrates of magnetite, pyroxene, and zircon from individual pumice clasts o...

[1] A recent prospective on the Yellowstone Caldera discounts its explosive potential based on inferences from tomographic studies which suggests a high degree of crystallization of the underlying magma body. In this study, we show that many of the first teleseismic P-wave arrivals observed at seismic stations on the edge of the caldera did not travel through the magma body but have taken longe...

To the Editor — Detailed analysis of volcanic materials1 allows the study of eruptions that have not been witnessed directly. Rotella et al.2 undertake the challenge of interpreting submarine volcaniclastic deposits around Macauley Volcano, part of the Kermadec Arc in the southwest Pacific Ocean. They propose a ‘Tangaroan’ eruption style, based on the textural characteristics of dredged pumice ...

These notes survey some basic results in toric varieties over a field F , with examples and applications. A computer algebra package (written by the author) is described which deals with both affine and projective toric varieties in any number of dimensions (written in both MAGMA [MAGMA] and GAP [GAP]). Among other things, the package implements the desingularization procedure, constructs some ...

[1] Volcanic SO2 can affect the Earth’s environment. Where no direct measurements of SO2 in the atmosphere are available, a petrologic method of assessing sulfur release from the magma must be used. However, in studies of arcderived eruptions, satellite-based measurements of SO2 emissions using Total Ozone Mapping Spectrometer (TOMS) data are orders of magnitude greater than those calculated pe...

[1] Fogo volcano, Cape Verde Islands, erupted in April 1995 after 43 years of dormancy. About 46 10 m of lava erupted during 7.5 weeks from vents on the SW flank of Pico do Fogo into Cha das Caldeiras. Interferograms obtained from 1993–1998 ERS SAR data show ground deformation due to the feeder dike but lack evidence for any volcano-wide deformation related to volume changes of a shallow magma ...

The rocky innards of the Earth locally melt to produce magma, which sometimes erupts as cataclysmic explosions. The energy released by these eruptions is matched only by that of large meteorite impacts. Whether large pools of magma generate huge volcanic eruptions, whose volume and duration can have global consequences for humanity, or solidify slowly within the Earth’s crust to form plutons (b...

Magma viscosity is strongly temperature-dependent. When hot magma flows in a conduit, heat is lost through the walls and the temperature decreases along the flow causing a viscosity increase. For particular values of the controlling parameters the steady-flow regime in a conduit shows two stable solutions belonging either to the slow or to the fast branch. As a consequence, this system may show...

Two volcanic eruptions in the Sumatra-Andaman arc that followed the disastrous M 9.3 earthquake of 26 December 2004 raise the question of whether these eruptions were triggered by the earthquake. Here we present new evidence to suggest that earthquake-induced decompression of the volcano magma systems leads to such eruptions. Numerical modeling reveals that other megathrust earthquakes induced ...

Silicic volcanic eruptions pose considerable hazards, yet the processes leading to these eruptions remain poorly known. A missing link is knowledge of the thermal history of magma feeding such eruptions, which largely controls crystallinity and therefore eruptability. We have determined the thermal history of individual zircon crystals from an eruption of the Taupo Volcanic Zone, New Zealand. R...