Collaborative research: Transport of magma in the near surface at small volcanoes- Experimental intrusion of basaltic melt into unconsolidated sediments

这个项目研究岩浆与物质的相互作用，岩浆通过这些物质上升到小体积的火山(地球上最丰富的火山地貌)。当岩浆相互作用涉及含有不同数量的水或冰的松散沉积物时，岩浆可能会以各种方式表现出来--穿过物质，引起爆炸，甚至在到达表面之前停止。这些不同的行为会影响火山喷发的方式，这个项目将增强预测未来喷发行为的能力，这对拯救生命和保护基础设施至关重要。该项目包括将30升(8加仑)玄武岩熔体注入不同类型的松散沉积物中的实验--干的、湿的和冻结的。这些实验提供了描述导致这些不同行为的岩浆和沉积物相互作用的条件的机会。受物理实验限制的条件的表征将通过计算机模拟和与受侵蚀的火山场(美国爱达荷州71古尔奇)的自然产物进行比较来扩展。这些实验是此类实验中的第一次，对岩浆流入沉积物提供了有价值的限制，将有助于更好地解释过去火山喷发的自然沉积，并为未来活动的模型提供投入。该项目将利用与科学界共享的成果和设施对本科生和研究生进行培训。与此同时，这些实验的新颖性将提供大量机会，通过视频和面向公众的博客吸引公众对科学和火山的兴趣。岩浆在近地表的行为直接影响喷发的可能性和由此产生的喷发方式。要到达地表，岩浆通常必须穿过松散的沉积物。这种相互作用影响了岩浆的运输、火山桩的稳定性以及火山喷发的可能性。玄武岩熔体-沉积物相互作用的米级实验将与计算模拟和现场工作相结合，以将实验结果和小型自然沉积物的规模与更广泛的自然情景联系起来。拟议的实验规模(毫米到米)足够大，足以与自然系统重叠(毫米到10‘S的米)。这些实验产品使用自动柱塞驱动的岩浆挤出装置创建，将进行数字建模，并与美国爱达荷州71号古尔奇火山类似大小的天然岩浆沉积物进行比较。这一区域包含了实验规模和更大规模的矿床，使其成为研究岩浆沉积相互作用的标度行为的理想的自然实验室。实验和数值结果将用于确定岩浆可用于机械混合和热相互作用的时间长度，有助于了解喷发是如何进行的，以及爆发岩浆-沉积物相互作用所必需的条件。具体地说，该项目将检验两个假设：1)在近地表条件下，侵入岩浆的流速和温度比沉积宿主条件更重要，它决定玄武岩岩浆是否会通过、与松散的沉积宿主混合或被阻止。2)玄武岩岩浆与松散沉积物混合的天然沉积物的结构和几何形状可用来估算形成时的通量速率和时间尺度。实验和数值结果将能够以前所未有的方式对自然沉积物中记录的力和热历史进行详细的定量解释。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This project deals with the interaction of magma and the materials through which it rises to feed small-volume volcanoes (the most abundant volcanic landforms on Earth). When magmatic interaction involves loose sediments that contain variable amounts of water or ice, the magma may behave in a variety of ways - passing through the material, causing explosions or even stopping before reaching the surface. These different behaviors influence how a volcano will erupt, and this project will enhance the ability to anticipate the behavior of future eruptions, which is vital for saving lives and protecting infrastructure. This project involves experiments that will inject 30 liters (8 gallons) of basaltic melt into different types of loose sediment - dry, wet, and frozen. The experiments provide the opportunity to characterize the conditions of magma and sediment interactions that result in these diverse behaviors. Characterization of conditions, which are limited by physical experiments will be expanded using computer simulations and comparison with natural products from an eroded volcanic field (71 Gulch, Idaho, USA). These experiments are the first of their kind and provide valuable constraints on the flow of magma into sediments and will help better interpret natural deposits of past volcanic eruptions and provide inputs for models of future activity. This project will involve the training of undergraduate and graduate students with results and facilities shared with the scientific community. At the same time, the novel nature of the experiments will provide ample opportunities to engage public interest in science and volcanoes through videos and public facing blogs. The behavior of magma in the near surface directly influences the potential for eruptions and their resulting eruptive styles. To reach the surface, magma commonly must travel through unconsolidated sediments. This interaction influences the transport of magma, the stability of volcanic piles, and the potential for phreatomagmatic explosions. Meter-scale experiments of basaltic melt-sediment interactions will be integrated with computational simulations and field work to bridge the scale from experimental results and small natural deposits to a wider range of natural scenarios. The scale of the proposed experiments (mm to m) is large enough to overlap with natural systems (mm to 10’s of m). The experimental products, created using an automated plunger-driven magma extrusion device, will be both modeled numerically and compared with similar-sized natural magma-sediment deposits at the 71 Gulch Volcano, Idaho, USA. This field area contains deposits at both the experimental scale and larger, making it an ideal natural laboratory to investigate the scaling behavior of magma sediment interactions. The experimental and numerical results will be used to determine how long magma is available for mechanical mixing and thermal interactions, contributing to an understanding of how eruptions progress, and what conditions are necessary for explosive magma-sediment interactions. Specifically, the project will test two hypotheses: 1) The flow rate and temperature of the intruding magma is more important than the sedimentary host conditions in determining whether basaltic magma will pass through, mingle with, or be arrested by an unconsolidated sedimentary host at near surface conditions. 2) The textures and geometries of natural deposits of mingled basaltic magma and unconsolidated sediments can be used to estimate the flux rate and time scale at the time of formation. Experimental and numerical results will enable detailed quantitative interpretations of the forces and thermal history recorded in natural deposits in ways not previously possible.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.