Reconstructing the plinian and co-ignimbrite sources of large volcanic eruptions: A novel approach for the Campanian Ignimbrite

Abstract

The 39 ka Campanian Ignimbrite (CI) super-eruption was the largest volcanic eruption of the past 200 ka in Europe. Tephra deposits indicate two distinct plume forming phases, Plinian and co-ignimbrite, characteristic of many caldera-forming eruptions. Previous numerical studies have characterized the eruption as a single-phase event, potentially leading to inaccurate assessment of eruption dynamics. To reconstruct the volume, intensity, and duration of the tephra dispersal, we applied a computational inversion method that explicitly accounts for the Plinian and co-ignimbrite phases and for gravitational spreading of the umbrella cloud. To verify the consistency of our results, we performed an additional single-phase inversion using an independent thickness dataset. Our better-fitting two-phase model suggests a higher mass eruption rate than previous studies, and estimates that 3/4 of the total fallout volume is co-ignimbrite in origin. Gravitational spreading of the umbrella cloud dominates tephra transport only within the first hundred kilometres due to strong stratospheric winds in our best-fit wind model. Finally, tephra fallout impacts would have interrupted the westward migration of modern hominid groups in Europe, possibly supporting the hypothesis of prolonged Neanderthal survival in South-Western Europe during the Middle to Upper Palaeolithic transition.

A chemostratigraphic study of the Campanian Ignimbrite eruption (Campi Flegrei, Italy): Insights on magma chamber withdrawal and deposit accumulation as revealed by compositionally zoned stratigraphic and facies framework

“…The CI eruption began with the onset of a sustained plinian plume, up to 39 km high, producing a stratified pumice lapilli fall deposit (5.3 km 3 of tephra) dispersed toward the East (Martì et al, 2016;. The plinian phase was followed by a collapsing column phase (Scarpati et al, 2014) during which an impressive pyroclastic density current was generated, spreading over an area of N30,000 km 2 and managing to surmount mountain ridges up to 1000 m high (Fisher et al, 1993).…”

Stress Field Control during Large Caldera-Forming Eruptions

“…Estimations of Mass Eruption Rates (MERs) obtained with different independent methods (Wilson and Walker, 1981;Hildreth and Mahood, 1986;Wilson and Hildreth, 1997;Baines and Sparks, 2005;Costa et al, 2014;Martí et al, 2016;Roche et al, 2016) indicate MERs of the orders 10 9 -10 11 kg/s (e.g., Bishop Tuff, Campanian Ignimbrite, Oruanui eruption, Taupo eruption, Peach Spring Tuff, Young Toba Tuff), implying durations of few to several hours only to evacuate even thousands of km 3 of magma.…”

Volcanic ash modeling with the online NMMB-MONARCH-ASH v1.0 model: model description, case simulation, and evaluation

“…Because of this strong dependence, uncertainties within 20 % in the determination of column height can translate into uncertainties up to 70 % for the MER (e.g., Biass and Bonadonna, 2011). Averaged column heights of eruptions that have not been directly observed are typically derived from characteristics of tephra deposits (e.g., Bonadonna and Costa, 2013;Carey and Sparks, 1986;Pyle, 1989) or are derived from model inversion (e.g., Connor and Connor, 2006;Marti et al, 2016;Pfeiffer et al, 2005). The empirical correlations to estimate MER in the model are described in Table 2 and are based either on fitting observations (e.g., Mastin et al, 2009) or more sophisticated fits accounting for wind bent-over effects (e.g., Degruyter …”