Magma degassing plays a fundamental role in controlling the style of volcanic eruptions. Whether a volcanic eruption is explosive, or effusive, is of crucial importance to approximately 500 million people living in the shadow of hazardous volcanoes worldwide. Studies of how gases exsolve and separate from magma prior to and during eruptions have been given new impetus by the emergence of more a...

The Eyjafjallajökull (Iceland) volcanic eruption of April-May 2010 caused unprecedented air-traffic disruption in Northern Europe, revealing some important weaknesses of current operational ash-monitoring and forecasting systems and encouraging the improvement of methods and procedures for supporting the activities of Volcanic Ash Advisory Centers (VAACs) better. In this work, we compare two es...

Volcanic eruptions of gassy magmas on Earth, Venus, and Mars produce plumes with markedly different fluid dynamics regimes. In large part the differences are caused by the differing atmospheric pressures and ratios of volcanic vent pressure to atmospheric pressure. For each of these planets, numerical simulations of an eruption of magma containing 4 weight percent gas were run on a workstation....

The measurement and analysis of seismicity in active volcanic areas is the main tool used in volcanic hazard mitigation. However, seismic monitoring technologies have met with only mixed success in forecasting eruptive episodes. This arises because, although our understanding of the spatio-temporal processes generating the observed seismic signals has increased substantially with the wide scale...

Significant new information shows that the Campanian Ignimbrite (CI) eruption from the Phlegrean Fields, southern Italy, was much larger than hitherto supposed and in fact one of the largest late Quaternary explosive events. The eruption can be dated to 40,000 calendar years ago, within the interval of the so-called Middle to Upper Paleolithic 'transition'. Its position can be precisely correla...

Monitoring gaseous and particulate volcanic emissions with remote observations is of particular importance for climate studies, air quality and natural risk assessment. The concurrent impact of the simultaneous presence of sulphur dioxide (SO2) emissions and the subsequently formed secondary sulphate aerosols (SSA) on the thermal infraRed (TIR) satellite observations is not yet well quantified....

[1] Low growth rates of atmospheric CO2 were observed following the 1991 Pinatubo (Luzon) volcanic eruption. One hypothesis for this CO2 anomaly is that since diffuse light is more efficiently used by forests than direct light, the increase in the diffuse fraction of sunlight due to scattering by volcanic sulfur aerosol in the years following the eruption substantially increased forest net prim...

The Toba Caldera in Indonesia is one of the most remarkable volcanic features formed during Quaternary geologic time. Its rich history of research for over a century has yielded important information on the physical volcanology of silicic calderas and super-eruptions, geochemical evolution of silicic magma bodies, and geophysical imaging of active sub-volcanic systems. During the past 1.3 my, t...

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 ...

[1] Probabilistic methods play an increasingly important role in volcanic hazards forecasts. Here we show that a probability distribution characterized by competing processes provides an excellent statistical fit (>99% confidence) to repose intervals between 75 vulcanian explosions of Soufrière Hills Volcano, Montserrat in September–October, 1997. The excellent fit is explained by a physical mo...