Modeling of Crater Floor Deformation in Relationship with Lava Lake Activity

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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.