Marti Alejandro, Folch Arnau, Costa Antonio, Engwell Samantha
Barcelona Supercomputing Center (BSC-CNS), Barcelona, Spain.
Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Bologna, Italy.
Sci Rep. 2016 Feb 17;6:21220. doi: 10.1038/srep21220.
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.
距今3.9万年的坎帕尼亚凝灰岩（CI）超级火山喷发是过去20万年欧洲规模最大的火山喷发。火山灰沉积物显示出两个不同的羽状物形成阶段，即普林尼式和同火山碎屑流，这是许多形成破火山口的火山喷发的特征。此前的数值研究将此次喷发描述为单相事件，这可能导致对喷发动力学的评估不准确。为了重建火山灰扩散的体积、强度和持续时间，我们应用了一种计算反演方法，该方法明确考虑了普林尼式和同火山碎屑流阶段以及伞状云的重力扩散。为了验证我们结果的一致性，我们使用一个独立的厚度数据集进行了额外的单相反演。我们拟合效果更好的两相模型表明，其质量喷发率高于此前的研究，并估计总沉降体积的3/4源自同火山碎屑流。在我们最佳拟合的风模型中，由于平流层强风，伞状云的重力扩散仅在最初的百公里内主导火山灰的传输。最后，火山灰沉降的影响可能打断了现代人类群体在欧洲的西迁，这可能支持了旧石器时代中期到晚期过渡阶段尼安德特人在欧洲西南部长期生存的假说。
