Volcanic ash fall is the most important cause for the existence and preservation of organic rich shales. If this hypothesis is confirmed, the implications are many. Formation of organic-rich shales correlates with high water column productivity rather than anoxia. Coastal upwelling occurs in about one percent of the world's oceans today. Upwelling concentrates sediments locally or regionally an...

Volcanic ash forecasting is a crucial tool in hazard assessment and operational volcano monitoring. Emission parameters such as plume height, total emission mass, and vertical distribution of the emission plume rate are essential and important in the implementation of volcanic ash models. Therefore, estimation of emission parameters using available observations through data assimilation could h...

Dielectric data in volcanic ash at weather radar wavelengths (centimeter range) are extremely sparse and are crucial for radar sensing of ash clouds and for imaging of volcanic terrains. This study extends previous data to include a wavelength range of 1.5-7.5 cm and volcanic ash compositions of 50-75 % silica. The real part of the complex permittivity, 2′, of volcanic ash is 6± 0.5 (1σ) for al...

Recent measurements of reactive trace gas species in volcanic plumes have offered intriguing hints at the chemistry occurring in the hot environment at volcanic vents. This has led to the recognition that volcanic vents should be regarded not only as passive sources of volcanic gases to the atmosphere, but also as 'reaction vessels' that unlock otherwise inert volcanic and atmospheric gas speci...

Hazard mapping in poorly known volcanic areas is complex since much evidence of volcanic and non-volcanic hazards is often hidden by vegetation and alteration. In this paper, we propose a semi-quantitative method based on hazard event tree and multi-hazard map constructions developed in the frame of the FP7 MIAVITA project. We applied this method to the Kanlaon volcano (Philippines), which is c...

The surficial deposits surrounding the Mount Meager volcanic complex include numerous avalanche deposits. These deposits share many attributes: (a) they are nearly monolithologic and comprise mainly intermediate volcanic rock clasts, (b) they lack internal structure, and (c) they are very poorly sorted. Despite these similarities, the avalanche deposits represent two distinct processes. Mass wa...

Volcanic ash contributed significantly to particulate matter (PM) in Iceland following the eruptions in Eyjafjallajökull 2010 and Grímsvötn 2011. This study aimed to investigate the association between different PM sources and emergency hospital visits for cardiorespiratory causes from 2007 to 2012. Indicators of PM10 sources; "volcanic ash", "dust storms", or "other sources" (traffic, firework...

The Azores archipelago is located in the Atlantic Ocean and is composed of nine volcanic islands. S. Miguel, the largest one, is formed by three active, E-W trending, trachytic central volcanoes with caldera (Sete Cidades, Fogo and Furnas). Chains of basaltic cinder cones link those major volcanic structures. An inactive trachytic central volcano (Povoação) and an old basaltic volcanic complex ...

Volcanic eruptions emit gases, ash particles and hydrometeors into the atmosphere, occasionally reaching heights of 20 km or more, to reside in the stratospheric overworld where they affect the radiative balance of the atmosphere and the Earth’s climate. Here we use satellite measurements and a Lagrangian particle dispersion model to determine the mass loadings, vertical penetration, horizontal...

Aggregation is a common process occurring in many diverse particulate gas mixtures (e.g. those derived from explosive volcanic eruptions, meteorite impact events, and fluid bed processing). It results from the collision and sticking of particles suspended in turbulent gas/air. To date, there is no generalized model of the underlying physical processes. Here, we investigate aggregates from 18 na...