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构成严重威胁。准确预测熔岩流侵位对减轻和管理灾害至关重要，需要对熔岩的物理性质有一定程度的了解，而这是目前尚不具备的。该项目将通过研究2018年夏威夷基拉韦厄火山喷发来改善这种理解。这次大规模喷发发生在较低的东部裂谷地带，其显著特点是体积大、速度快和气泡比例大。这次喷发的一个独特之处也是对就地流动进行了前所未有的高质量直接观测，包括无人机收集的高分辨率熔岩流动视频。该小组将利用夏威夷的观测结果，结合熔岩流动的数学模型、从熔岩流动中收集的样本分析以及利用气泡悬浮液进行的实验室实验，来提高预测火山喷发如何演变并减轻其危险的能力。此外，该项目将让教育工作者和学生参与，并根据喷发制作教育材料，以促进科学素养和更广泛的参与。这是一个由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理事会(NERC)通过NSF/GEO-NERC牵头机构协议共同资助的项目。该协定允许美国和英国提交一个单一的联合提案，并由该机构进行同行审查，该机构的调查员在预算中所占比例最大。在成功地联合确定一个奖项后，每个机构都会为预算的比例和与自己国家(在这种情况下是达勒姆大学)相关的调查人员提供资金。其中一个挑战是，熔岩是一种复杂的流体，包含液体熔体、气泡和固体晶体，所有这些都共同作用来确定熔岩的行为。这种相互作用在熔岩前进的过程中发生了变化，因为晶体的形成、气泡的离开和熔体的冷却。该项目将通过解决两个问题来解决这一挑战：1)多相熔岩流变学在侵位过程中如何演变；2)流变学如何影响侵位。2018年夏威夷基拉韦厄火山(KLERZ)下东裂谷地带的喷发提供了一个前所未有的详细研究熔岩侵位的机会。在喷发期间，无人驾驶航空系统(UAS)捕捉到了独特的综合时间序列，拍摄到了通道化熔岩的空中视频。这项研究将基于对熔岩流变学耦合演化的新的、定量的理解，为预测熔岩流侵位创造一个新的物理-数学框架。我们将利用史无前例的相互关联的现场数据集，并将它们与沟道化多相流的模拟实验以及天然和模拟多相样品的实验室测量相结合，以研究不同长度尺度下的多相流变性和流动。该团队将：1)对KLERZ熔岩样品进行实验室流变学和微观结构分析；2)使用UAS数据描述KLERZ槽化流动的演变；3)使用比例熔岩类似物来构建和校准基本物理模型；4)综合所有观测数据，生成KLERZ熔岩的尺度敏感流变学定律；以及5)整合现有流动定位模型中的新流变关系，并测试KLERZ流场上的流变关系。拟议研究的核心成果将是一个经过验证的预测熔岩流侵位的量化框架。这一成果预计将改善对火山灾害的评估和减轻。此外，所有来自模拟实验的数值模型和测量都将开放，以便它们可以作为未来模型的基准。这项研究将使科学家和从业人员能够确定自然系统的物质属性和流动行为，并反过来利用对熔岩侵位的现场观察来推断熔岩的属性。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。

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.