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A global synthesis of lava lake dynamics

机译：熔岩湖动力学的全球综合

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Active lava lakes represent a variety of open-vent volcanism in which a sizable body of lava accumulates at the top of the magma column, constrained by the vent and/or crater geometry. The longevity of lava lakes reflects a balancing of cooling and outgassing occurring at the surface and input of hot and gas-rich magma from below. Due to their longevity and relative accessibility, lava lakes provide a natural laboratory for studying fundamental volcanic processes such as degassing, convection and cooling. This article examines all seven lakes that existed at the time of writing in 2018, located in the Pacific, Antarctica, Africa, and South and Central America. These lakes span all tectonic environments, and a range of magma compositions. We focus on analysis of the lake surface motion using image velocimetry, which reveals both similarities and contrasts in outgassing and lake dynamics when comparing the different lakes. We identify two categories of lake behavior: Organized (Erta'Ale, Nyiragongo, Kilauea after 2011, and Erebus) and Chaotic (Villarrica, Masaya, Marum). This division does not map directly to lake size, viscosity, gas emission rate, or temperature. Instead, when examined together, we find that the lakes follow a linear relationship between average surface speed and the ratio of total gas flux to lake surface area. This relationship points to the combined importance of both flux and lake size in addition to the total volume of gas emission, and suggests that a shared deep mechanism controls the supply of heat and gas to all lakes. On the other hand, the differences between Chaotic and Organized lakes highlight the important role of the geometry of the conduit-lake transition, which superimposes a shallow signal on that of the deep circulation. The spatial patterns of surface motion we document suggest that the release of gas bubbles at Chaotic lakes is more efficient (i.e., bubbles are less likely to be retained and recycled) compared with Organized lakes. In addition, the data presented here indicate that the solidified crust of Organized lakes plays a role in regulating convection and outgassing in lava lakes. (C) 2019 Elsevier B.V. All rights reserved.
机译：活跃的熔岩湖代表着各种开放式火山活动，其中大量的熔岩堆积在岩浆柱的顶部，受到火山口和/或火山口几何形状的限制。熔岩湖的寿命反映出地表冷却和除气的平衡，以及从下方输入热气丰富的岩浆的平衡。由于熔岩湖的长寿性和相对可及性，它们为研究基本的火山作用过程（例如脱气，对流和冷却）提供了天然的实验室。本文研究了撰写本文时截至2018年存在的所有七个湖泊，它们位于太平洋，南极洲，非洲以及南美洲和中美洲。这些湖泊横跨所有构造环境和一系列岩浆成分。我们专注于使用图像测速仪分析湖泊表面运动，当比较不同的湖泊时，它揭示了放气和湖泊动力学的相似性和对比性。我们确定了两类湖泊行为：有组织的（Erta'Ale，Nyiragongo，2011年之后的基拉韦厄和Erebus）和混沌的（Villarrica，Masaya，Marum）。此划分未直接映射到湖泊大小，粘度，气体排放速率或温度。相反，当一起检查时，我们发现湖泊遵循平均表面速度与总气体通量与湖泊表面积之比之间的线性关系。这种关系指出了通量和湖泊大小以及气体排放总量的综合重要性，并暗示了一种共享的深度机制控制着向所有湖泊的热量和气体供应。另一方面，混沌湖泊和有组织湖泊之间的差异突出了导管湖过渡的几何形状的重要作用，这将浅层信号叠加在深层环流上。我们记录的表面运动的空间格局表明，与有组织的湖泊相比，在混沌湖中释放气泡更有效（即气泡不太可能被保留和再循环）。此外，这里提供的数据表明，有组织的湖泊的凝固壳在调节熔岩湖的对流和除气方面发挥了作用。 （C）2019 Elsevier B.V.保留所有权利。

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