Modeling of Crater Floor Deformation in Relationship with Lava Lake Activity

火山会产生自然灾害（熔岩流、火山灰、地震等），对当地居民和经济构成威胁。这个项目旨在更好地了解火山是如何工作的，并预测未来的喷发，了解火山下面的岩浆在哪里以及有多少。火山下的岩浆管道和储存区构成了岩浆管道系统。熔岩湖为了解岩浆管道系统的表层提供了一个独特的窗口。然而，地球上只有少数火山拥有永久的熔岩湖（半）。刚果民主共和国的尼拉贡戈火山拥有地球上最大的熔岩湖。尼亚穆拉吉拉火山是尼拉贡戈火山的邻居，自2014年以来，在一个坑火山口里也有一个小熔岩湖。通过成像这些火山顶部熔岩湖周围的地面变形，我们可以模拟和可视化岩浆管道系统。本项目分析的两座火山是危险的，可以迅速从露天熔岩湖活动过渡到危险和快速的喷发。特别是，尼拉贡戈火山造成的危害是相当大的，2002年的最后一次致命喷发就突显了这一点。鉴于美国（夏威夷）和其他地方的其他火山与刚果火山有相似之处，这里提出的研究对全球的火山和喷发预测具有广泛的意义。该项目是与比利时的科学家合作进行的，将支持宾夕法尼亚州立大学的研究、研究生和本科生教育和培训。这个项目将在两座拥有熔岩湖的危险火山上解决以下问题：是什么导致尼拉贡戈火山和尼亚穆拉吉拉火山（刚果民主共和国）的火山口底部变形？该项目将利用最近在尼拉贡戈火山和尼亚穆拉吉拉火山（刚果民主共和国）获得的空间和时间密集的合成孔径雷达（SAR）数据集。这些密集数据集采用最近开发的InSAR时间序列方法，即多维小基线子集（MSBAS）方法（Samsonov和d'Oreye, 2012）进行处理，该方法允许在相同的SBAS算法中摄取不同的卫星和轨道，以输出详细的地面位移时间序列。然后，该项目将致力于模拟在不同熔岩湖活动期间在两座火山山顶观测到的地表变形。火山口底部的地面变形是由于以下一个或多个因素造成的，每个因素都需要在每个火山上进行彻底的调查和测试：熔岩流冷却和下沉，浅层储层的压力变化，火山口环断层的运动，岩浆侵入冷却和下沉。通过整合采用创新时间序列方法处理的多个遥感大地测量（地表变形）数据集，以及其他基于遥感的熔岩湖表面高度、热异常和气体（即SO2），以及其他地面测量（如地震和气体），将开发两个火山系统的岩浆管道系统浅层部分的概念模型。该项目由极端事件预测和恢复能力（PREEVENTS）项目共同资助。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。

Volcanoes create natural hazards (lava flows, ash plumes, earthquakes etc.) that can pose risk to the local population and economy. This project aims to better understand how volcanoes work and forecast future eruptions, knowing where and how much magma is located beneath the volcano. Magma conduits and storage areas beneath a volcano constitute the magma plumbing system. Lava lakes offer a unique window into the superficial part of a magma plumbing system. However, only a few volcanoes on Earth host a lava lake (semi-) permanently. Nyiragongo Volcano in the Democratic Republic of Congo, hosts the largest lava lake on Earth. Nyamulagira Volcano, the neighbor of Nyiragongo Volcano, also hosts a small lava lake in a pit crater since 2014. By imaging the ground deformation around lava lakes in the summit areas of those volcanoes, we can model and visualize the magma plumbing system. The two volcanoes targeted for analysis in this project are hazardous and can quickly transition from open-vent lava lake activity to dangerous and fast eruptions. In particular, the hazards posed by Nyiragongo are considerable, as highlighted by the last deadly eruption in 2002. Given that other volcanoes in the U.S. (Hawaii) and elsewhere share similarities with the Congo volcanoes, the research proposed here has broad implications for volcanoes and eruption forecasting worldwide. This project is conducted in collaboration with scientists in Belgium and will support research and graduate and undergraduate education and training at Pennsylvania State University. This project will address the following question at two hazardous volcanoes hosting lava lakes: What is causing the deformation of Nyiragongo and Nyamulagira (Democratic Republic of Congo)'s crater floors? The project will take advantage of recent spatially and temporally dense Synthetic Aperture Radar (SAR) datasets acquired over Nyiragongo and Nyamulagira volcanoes (Democratic Republic of Congo). Those dense datasets are processed with a recently developed InSAR time series approach, the Multidimensional Small BAseline Subset (MSBAS) method (Samsonov and d'Oreye, 2012) that allows to ingest different satellite and orbits within the same SBAS algorithm to output a detailed time-series of ground displacements. Then, the project will aim to model the ground surface deformation observed in the summit areas of both volcanoes during periods of various lava lake activity. The ground deformation of the crater floors is due to one, or a combination of, the following factors that will each need to be thoroughly investigated and tested at each volcano: lava flow cooling and subsidence, pressure changes in a shallow reservoir, motion along caldera ring faults, and magma intrusion cooling and subsidence. By integrating several remote sensing geodetic (ground surface deformation) datasets processed with an innovative time series approach, with other remote sensing based lava lake surface heights, thermal anomalies and gas (i.e., SO2), together with other ground-based measurements such as seismic and gas, a conceptual model of the shallow part of the magma plumbing system will be developed at two volcanic systems. This project is cofunded by the Prediction of and Resilience against Extreme Events (PREEVENTS) program.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.