Modeling of Crater Floor Deformation in Relationship with Lava Lake Activity

火山造成自然灾害(熔岩流、火山灰羽流、地震等)这可能会给当地人口和经济带来风险。该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，了解火山下方的位置和多少岩浆。火山下方的岩浆管道和储存区构成了岩浆管道系统。熔岩湖提供了一扇独特的窗口，可以看到岩浆管道系统的表层。然而，地球上只有几座火山(半)永久地拥有熔岩湖。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。尼拉贡戈火山的邻居尼亚穆拉吉拉火山自2014年以来也在坑中拥有一个小熔岩湖。通过成像这些火山顶端地区熔岩湖周围的地面变形，我们可以对岩浆管道系统进行建模和可视化。本项目分析的两座火山是危险的，可以迅速从开放喷口的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相当大，正如2002年最后一次致命喷发所强调的那样。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，这里提出的研究对世界范围内的火山和喷发预测具有广泛的影响。该项目是与比利时科学家合作进行的，将支持宾夕法尼亚州立大学的研究、研究生和本科教育和培训。该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和尼亚穆拉吉拉(刚果民主共和国)的S陨石坑底部变形？该项目将利用最近在尼拉贡戈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数据集。使用最近开发的InSAR时间序列方法--多维小基线子集(MSBAS)方法(Samsonov和d‘Oreye，2012)处理这些密集数据集，该方法允许在同一SBAS算法内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，该项目的目标是对两座火山顶端地区在不同熔岩湖活动期间观察到的地表变形进行建模。火山口底部的地面变形是由于以下一种或多种因素造成的，每一种因素都需要在每一座火山上进行彻底的调查和测试：熔岩流冷却和沉降、浅层水库的压力变化、沿火山口环断层的运动以及岩浆侵入冷却和沉降。通过将以创新的时间序列方法处理的若干遥感大地测量(地表形变)数据集与其他基于遥感的熔岩湖表面高度、热异常和气体(即二氧化硫)以及地震和气体等其他陆基测量相结合，将在两个火山系统建立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抵御极端事件(PREEVENTS)计划共同资助。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。

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.