The eruption of the Campanian Ignimbrite. DISTAR study.

The results of a study conducted entirely by researchers from the Department of Earth, Environmental and Resource Sciences at the University of Frederick and published in Scientific Reports, from the nature research group, illustrate the reconstruction of the largest eruptive event in the Neapolitan-Flegrean area: the eruption of the Campanian Ignimbrite, which occurred 39,000 years ago.

Large ignimbrites are the product of devastating explosive eruptions that have repeatedly affected climate on a global scale. Detailed reconstruction of the vertical and lateral facies variations of this ignimbrite (tuff), scattered over the entire Campanian region, has made it possible to constrain the physical characters of the pyroclastic current that generated it. The eruption begins with an eruptive column that oscillates for about 20 hours between 23 and 38 km in height, dispersing eastward a blanket of pumiceous lapilli. The collapse of this eruptive column produces a turbulent pyroclastic current, about 1.5 km thick. This second phase lasts 7 hours, emitting 67 km3^of magma. The pyroclastic current advances radially at an estimated velocity of 220 m/s invading the entire Campanian Plain, overtopping the reliefs bordering it and deeply eroding the substrate. An increase in eruptive flow, after about 30 minutes, pushes the current more than 80 km from the Phlegraean Fields. The temperature of the accumulating products is so high that it causes them to weld. During this climax phase, the pyroclastic current creates a no-sedimentation zone or bypass around the Phlegraean Fields. After about six hours, the pyroclastic current begins to retreat toward the source, invading increasingly narrow areas, and leaving a trail of large decimeter pumices from Caserta to Capri. The event ends with the collapse of the emission area and the formation of the Phlegrean caldera. During the latter phase, breccia successions erupted and accumulated along the edge of the caldera. This study illustrates how large pyroclastic currents can evolve in time and space and the importance of internal (eruptive and transport mechanisms) and external (topography, surface water and rainfall) factors that regulate their behavior.

Scarpati, C., Sparice, D. & Perrotta, A. Dynamics of large pyroclastic currents inferred by the internal architecture of the Campanian Ignimbrite. Sci Rep 10, 22230 (2020). https://doi. org/10.1038/s41598-020-79164-7

The article can be downloaded for free at the following link: https: //rdcu.be/ccmM4