We have developed the first experimental methodology to create a volcanic spatter pile using molten basalt. This method permits reproduction of thermal conditions that yield the wide variety of spatter morphologies observed in nature. The morphology of the clasts is most strongly controlled by the time the clast spends above the glass transition temperature, which is in turn affected by the rate of accumulation and cooling of the deposit. Also, spatter piles that remain hotter over longer durations experience increased fusion between clasts, less void space between clasts, and generally larger aspect ratios. Our experimental method successfully replicated natural microcrystal textures, rheology, and clast size. Work is still therefore required to achieve realistic vesicle distribution and deposit void space. Based on presented experimental work, we estimate emplacement conditions of Southern Idaho spatter vents to have been ~ 850–900 °C, with eruption temperatures closer to 1000–1100 °C. The rapid decrease from eruption temperature to effective emplacement temperature is the result of clast flight as well as equilibrating with the cooler surrounding material. The morphology of the natural clasts matches experiments that have accumulation rates of 2.5–4.5 m/h, which also is consistent with the few measurements made at active eruptions. Finally, we provide a constraint on the temperatures and accumulation rates that can lead to the construction of fused spatter features, as well as provide the steps for future experiments to investigate other aspects (such as compression, impact, and larger sizes) of spatter formation by adapting our methodology.

中文翻译：

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飞溅稳定性：用实验弹形态限制累积速率和温度条件

我们开发了第一个使用熔融玄武岩创建火山飞溅堆的实验方法。这种方法允许重现产生在自然界中观察到的各种飞溅形态的热条件。碎屑的形态最受碎屑在玻璃化转变温度以上的时间的控制，而玻璃化转变温度又受到沉积物的积累和冷却速度的影响。此外，在较长时间内保持较高温度的飞溅堆会增加碎屑之间的融合，碎屑之间的空隙空间更小，并且通常具有更大的纵横比。我们的实验方法成功地复制了天然微晶纹理、流变学和碎屑尺寸。因此仍然需要工作来实现现实的囊泡分布和沉积空隙空间。根据提出的实验工作，我们估计爱达荷州南部飞溅喷口的就位条件约为 850–900 °C，喷发温度接近 1000–1100 °C。从喷发温度到有效侵位温度的快速下降是碎屑飞行以及与较冷的周围材料平衡的结果。天然碎屑的形态与积累率为 2.5-4.5 m/h 的实验相匹配，这也与在活动喷发时进行的少数测量结果一致。最后，我们提供了对温度和累积速率的限制，这可以导致构建融合飞溅特征，并为未来的实验提供步骤以研究飞溅形成的其他方面（例如压缩、冲击和更大尺寸）通过调整我们的方法。