Science Daily May 27, 2024
Explosive volcanic eruptions driven by magmatic fragmentation or steam expansion produce hazardous atmospheric plumes composed of tephra particles, hot gas, and entrained air. However, an eruption mechanism outside this phreatic–magmatic spectrum was suggested by a sequence of 12 explosive eruptions in May 2018 at KÄ«lauea, Hawaii, that occurred during the early stages of caldera collapse and produced atmospheric plumes reaching 8 km above the vent. A team of researchers in the US (US Geological Survey Volcano Science Center California Volcano Observatory, University of Oregon, USGS Portland, USGS Vancouver, WA) used seismic inversions for reservoir pressure as a source condition for three-dimensional simulations of transient multiphase eruptive plume ascent through a conduit and stratified atmosphere. They found that the plumes were consistent with eruptions caused by the abrupt subsidence of reservoir roof rock that increased pressure in the underlying magma reservoir. In their model, the reservoir was overlain by a pocket of accumulated high-temperature magmatic gas and lithic debris, which were driven through a conduit approximately 600 m long to erupt particles at rates of around 3,000 m3 s−1. Their results revealed a distinct collapse-driven type of eruption and provided a framework for integrating diverse geophysical and atmospheric data with simulations to gain a better understanding of unsteady explosive eruptions…read more. TECHNICAL ARTICLE
Collapse-driven eruption mechanism. Credit: Nature Geoscience, May 27, 2024