Dellino Pierfrancesco, Dioguardi Fabio, Rinaldi Anna, Sulpizio Roberto, Mele Daniela
Dipartimento Di Scienze Della Terra E Geoambientali, Università Di Bari, Bari, Italy.
British Geological Survey, The Lyell Centre, Edinburgh, UK.
Sci Rep. 2021 Oct 25;11(1):21024. doi: 10.1038/s41598-021-00395-3.
Pyroclastic density currents are ground hugging gas-particle flows associated to explosive volcanic eruptions and moving down a volcano's slope, causing devastation and deaths. Because of the hostile nature they cannot be analyzed directly and most of their fluid dynamic behavior is reconstructed by the deposits left in the geological record, which frequently show peculiar structures such as ripples and dune bedforms. Here, a set of equations is simplified to link flow behavior to particle motion and deposition. This allows to construct a phase diagram by which impact parameters of dilute pyroclastic density currents, representing important factors of hazard, can be calculated by inverting bedforms wavelength and grain size, without the need of more complex models that require extensive work in the laboratory.
火山碎屑密度流是与火山爆发相关的紧贴地面的气粒流，沿火山斜坡向下移动，造成破坏和人员伤亡。由于其危险性，无法直接对其进行分析，其大部分流体动力学行为是通过地质记录中留下的沉积物重建的，这些沉积物经常呈现出诸如波纹和沙丘等特殊结构。在此，一组方程被简化，以将流动行为与颗粒运动和沉积联系起来。这使得可以构建一个相图，通过该相图，代表危险重要因素的稀释火山碎屑密度流的冲击参数可以通过反转床形波长和粒度来计算，而无需使用需要在实验室进行大量工作的更复杂模型。
