NSF/GEO-NERC: Collaborative Research: Multi-scale investigation of rheology and emplacement of multi-phase lava

熔岩流使社区流离失所，摧毁房屋和基础设施，并可能对生命和健康造成严重危害。准确预测熔岩流的就位对减轻和管理危险至关重要，需要对熔岩的物理性质有一定程度的了解，而目前还没有这种了解。该项目将通过研究2018年夏威夷基拉韦厄火山的喷发来提高人们的认识。这次大喷发发生在东部下裂谷带，其体积大、速度快、气泡占比大。这次火山喷发的一个独特之处在于对现场流动的高质量直接观测，包括由无人机收集的高分辨率熔岩流动视频。该团队将利用夏威夷的观测结果，结合熔岩流的数学模型，对从熔岩流中收集的样本进行分析，并利用气泡悬浮液进行实验室实验，以提高预测火山爆发演变和减轻其危害的能力。此外，该项目还将包括教育工作者和学生，并制作以火山爆发为基础的教育材料，以促进科学素养和扩大参与。该项目由美国国家科学基金会地球科学理事会（NSF/GEO）和英国国家环境研究委员会（NERC）通过NSF/GEO-NERC牵头机构协议共同资助。该协议允许美国/英国提交一份联合提案，并由其调查员拥有最大比例预算的机构进行同行评审。在成功地共同确定一项奖励后，每个机构资助预算的比例和与本国有关的调查人员（在这种情况下是达勒姆大学）。其中一个挑战是，熔岩是一种复杂的流体，它包含液体熔体、气泡和固体晶体，所有这些因素共同决定了熔岩的行为。在熔岩前进的过程中，这种相互作用随着晶体的形成、气泡的离开和熔体的冷却而改变。本项目将通过解决以下两个问题来应对这一挑战：1)多相熔岩流变学在就位过程中如何演变；2)流变如何影响就位。2018年夏威夷基拉韦厄火山（KLERZ）下东部裂谷区的喷发提供了一个前所未有的详细研究熔岩位置的机会。在火山喷发期间，无人驾驶航空系统（UAS）捕捉到一个独特的综合时间序列的架空视频通道化熔岩。本研究将基于对熔岩流变耦合演化的新的定量认识，为预测熔岩流侵位建立一个新的物理-数学框架。我们将利用前所未有的、相互关联的现场数据集，并将它们与渠化多相流的模拟实验以及自然和模拟多相样品的实验室测量相结合，在一定长度范围内研究多相流变学和流动。该团队将：1)对KLERZ样品进行实验室流变学和微观结构分析；2)利用UAS数据表征KLERZ通道化流的演变；3)使用缩放熔岩模拟物构建和校准基本物理模型；4)综合所有观测结果，得出KLERZ熔岩的尺度敏感流变规律；5)在现有流位模型中整合新的流变关系，并在KLERZ流场上进行测试。拟议研究的核心成果将是预测熔岩流就位的有效定量框架。预计这一结果将改善火山灾害的评估和缓解工作。此外，所有数值模型和模拟实验的测量结果都将公开，以便它们可以用作未来模型的基准。这项研究将使科学家和实践者能够确定自然系统的物质特性和流动行为，反过来，通过对熔岩就位的实地观察来推断熔岩的特性。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Lava flows displace communities, destroy homes and infrastructure, and can pose a serious hazard to life and health. Accurate forecasting of lava flow emplacement is essential to hazard mitigation and management, and requires a level of understanding of the physical properties of lava which is not currently available. This project will focus on improving this understanding by examining the 2018 eruption of Kilauea volcano, in Hawai'i. This large eruption took place on the lower east rift zone, and was significant in its large volume, fast speeds, and large fraction of gas bubbles. A unique aspect of this eruption is also the unprecedented volume of high-quality direct observations of in-situ flow, including high-resolution videos of flowing lava collected by drones. The team will use the observations from Hawai'i together with mathematical models of lava flows, analysis of samples collected from the flow, and laboratory experiments utilizing bubbly suspensions, to advance the ability to forecast how volcanic eruptions evolve and mitigate their hazards. In addition, the project will involve educators and students and produce educational materials based on the eruption, to promote science literacy and broaden participation. This is a project that is jointly funded by the National Science Foundation's Directorate of Geosciences (NSF/GEO) and the National Environment Research Council (NERC) of the United Kingdom (UK) via the NSF/GEO-NERC Lead Agency Agreement. This Agreement allows a single joint US/UK proposal to be submitted and peer-reviewed by the Agency whose investigator has the largest proportion of the budget. Upon successful joint determination of an award, each Agency funds the proportion of the budget and the investigators associated with its own country (in this case, Durham University).One of the challenges is that lava is a complex fluid that contains liquid melt, gas bubbles, and solid crystals, all acting together to determine the lava's behavior. This interaction changes during the advancement of the lava as crystals form, bubbles leave and the melt cools. This project will address this challenge by resolving two issues: 1) how multi-phase lava rheology evolves during emplacement; 2) how rheology impacts emplacement. The 2018 eruption at the Lower East Rift Zone of Kilauea Volcano in Hawaii (KLERZ) provides an opportunity to investigate lava emplacement in unprecedented detail. During the eruption, Unoccupied Aerial Systems (UAS) captured a uniquely comprehensive time-series of overhead videos of channelized lava. This study will create a new physical-mathematical framework for predicting lava flow emplacement based on new, quantitative understanding of the coupled evolution of lava rheology. We will leverage unprecedented, linked field data sets and combine them with analog experiments of channelized multi-phase flows and laboratory measurements of natural and analog mutliphase samples to investigate multi-phase rheology and flow at a range of length scales. This team will: 1) Perform laboratory rheometry and microstructure analysis of KLERZ samples; 2) Use UAS data to characterize the evolution of KLERZ channelized flows; 3) Used scaled lava analogues to construct and calibrate fundamental physical models; 4) Synthesize all observations to produce scale-sensitive rheological laws for KLERZ lavas; and 5) Integrate new rheological relations in existing flow emplacement models and test those on KLERZ flow field. The core deliverable of the proposed research will be a validated quantitative framework for predicting lava flow emplacement. This outcome is expected to improve assessment and mitigation of volcanic hazards. In addition, all numerical models and measurements from analog experiments will be made open, so that they can be used as benchmarks for future models. This study will enable scientists and practitioners to determine material properties and flow behavior of the natural system and, conversely, to use field observations of lava emplacement to deduce the properties of the lava.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.