The fundamental role of ice particle collisions in the separation of electric charge and generation of lightning in thunderclouds is now reasonably well established (Latham, 1981; Williams, 1985; Saunders, 1995). Charge separation and lightning are also prevalent in volcanic eruptions. A recent literature survey by McNutt and Davis (2000), and its recent extension, has shown more than 150 incid...

In explosive submarine eruptions, volcanic jets transport fragmented tephra and exsolved gases from the conduit into water column. Upon eruption jet mixes with seawater rapidly cools. This mixing associated heat transfer ultimately determines whether steam present in will completely condense or rise to breach sea surface become a subaerial hazard. We develop multiphase model subgrid calculation...

The Ethiopian Rift Valley hosts the longest record of human co-existence with volcanoes on Earth, however, current understanding of the magnitude and timing of large explosive eruptions in this region is poor. Detailed records of volcanism are essential for interpreting the palaeoenvironments occupied by our hominin ancestors; and also for evaluating the volcanic hazards posed to the 10 million...

The largest explosive volcanic eruptions (supereruptions) produce >1000 km3 of ejected material and ≥1000 Mt (1015 g) of submicron atmospheric aerosols and dust. These eruptions may be capable of creating global climatic disturbances sufficient to cause severe problems for world agriculture and modern civilization. Supereruptions are estimated to occur on average about every 50,000 years, which...

During explosive eruptions, airborne particles collide and stick together, accelerating the fallout of volcanic ash and climate-forcing aerosols. This aggregation process remains a major source of uncertainty both in ash dispersal forecasting and interpretation of eruptions from the geological record. Here we illuminate the mechanisms and timescales of particle aggregation from a well-character...

We report exploratory experiments simulating gas-driven eruptions using the C02H20 system at room temperature as an analog of natural eruptive systems. The experimental apparatus consists of a test cell and a large tank. Initially, up to 1.0 wt % of C02 is dissolved in liquid water under a pressure of up to 735 kPa in the test cell. The experiment is initiated by suddenly reducing the pressure ...