There are ~750 active and potentially active volcanoes in Southeast Asia. Ash from eruptions of volcanic explosivity index 3 (VEI 3) and smaller pose mostly local hazards while eruptions of VEI ≥ 4 could disrupt trade, travel, and daily life in large parts of the region. We classify Southeast Asian volcanoes into five groups, using their morphology and, where known, their eruptive history and d...

BACKGROUND The eruptions of Eyjafjallajökull (2010) and Grímsvötn (2011), Iceland, triggered immediate, international consideration of the respiratory health hazard of inhaling volcanic ash, and prompted the need to estimate the potential hazard posed by future eruptions of Iceland's volcanoes to Icelandic and Northern European populations. METHODS A physicochemical characterization and toxic...

Abstract Bubble and crystal textures evolve during magma ascent, altering properties that control ascent such as permeability viscosity. Eruption style results from feedbacks between bubble nucleation growth, microlite crystallization, gas loss, all processes recorded in pyroclasts. We show pyroclasts of the mafic Curacautín ignimbrite Llaima volcano, Chile, record a history repeated autobrecci...

Dissolved gas in liquid is able to power violent eruptions. Two kinds of such gas-driven eruptions are known in nature: explosive volcanic eruptions driven by dissolved H2O in magma at high temperatures and lake eruptions driven by dissolved CO2 in water at low temperatures. There are two known occurrences of lake eruptions, one in 1984 (Lake Monoun) and one in 1986 (Lake Nyos), both in Cameroo...

Understanding the mechanisms that govern ash aggregation is of critical importance in volcanology. Aggregation reduces the residence time of ash (≤2 mm) in the atmosphere strongly, by enhancing the sedimentation of finer-grained material generated during explosive eruptions. To date, experimental studies have focused on the expectation that water provides the strongest bonds between particles t...