Outgassing behaviour during highly explosive basaltic eruptions
Outgassing behaviour during highly explosive basaltic eruptions
复制标题
DOI：
10.1038/s43247-023-01182-w
复制
发表时间：
2024-01-02
影响因子：
7.9
通讯作者：
Burton，Mike R.
中科院分区：
文献类型：
--
作者：
Bamber，Emily C.;La Spina，Giuseppe;Burton，Mike R.
玄武岩喷发的爆炸性与上升过程中溶解气体与熔体分离的效率有关，而该效率受岩浆渗透性控制。然而，不同爆炸性喷发产生的玄武岩火山碎屑可以表现出相似的渗透性，这表明渗透性、排气和喷发类型之间可能存在复杂的关系。在这里，我们使用 X 射线显微断层扫描提供玄武岩火山碎屑的 3D 测量。我们通过使用数值管道模型研究渗透率和释气对岩浆上升动力学的作用。在渗透性参数中，气泡数密度和摩擦系数对爆炸性影响较大。然而，对于快速上升的玄武岩岩浆，气体-熔体耦合保持独立于岩浆渗透率。在这种情况下，岩浆储存条件可能决定喷发方式，驱动岩浆快速上升、结晶和气泡成核，产生高度爆炸性喷发。揭示喷发前状况的监测参数可能有助于减轻灾害，特别是对于表现出多种喷发类型的玄武岩系统。
Explosivity of basaltic eruptions is related to the efficiency in which exsolved gas can separate from the melt during ascent, which is controlled by magma permeability. However, basaltic pyroclasts from eruptions of varying explosivity can show similar permeability, indicating a possible complex relationship between permeability, outgassing and eruptive style. Here, we provide 3D measurements of basaltic pyroclasts using X-ray microtomography. We investigate the role of permeability and outgassing on magma ascent dynamics by using a numerical conduit model. Among the permeable parameters, bubble number density and friction coefficient largely affect explosivity. However, for fast ascending basaltic magmas, gas-melt coupling is maintained independent of magma permeability. In this case, magma storage conditions may determine eruptive style, driving rapid magma ascent, crystallisation and bubble nucleation, producing a highly explosive eruption. Monitoring parameters which reveal pre-eruptive conditions may assist hazard mitigation, particularly for basaltic systems which exhibit a wide range in eruptive style.