SeisMic Observations of deep VolcAnic pRocesses

• Applicants: Professor Dr. Georg Rümpker; Dr. Christoph Sens-Schönfelder
• Subject Area: Geophysics
• Term: from 2020 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 443363136

We aim to study pre-eruptive processes in the deep parts of plumbing systems in subduction zone volcanoes based on seismological observations. Volcanoes are fed by melts that are generated in the mantle and ascend to the surface through a complex and elusive plumbing system that combines pervasive and focused flows and multi-level reservoirs. The processes in the volcano-magmatic systems can be studied based on their seismological manifestations. Pressure variations caused by magma and gas transport generate specific seismic signals as well as stress variations in the surrounding rock that result in variations of its elastic properties.Largest and most dangerous explosive volcanic eruptions are fed from a few kilometers deep magmatic reservoirs. Currently, most seismological observations reflect the shallow pre-eruptive activity. At the same time fully understanding the functioning of volcanic systems and detecting earliest signs of volcanic re-activation requires observations of the processes in the deep volcanic roots. For this purpose, we will study the Klyuchevskoy Volcanic Group (KVG) in Kamchatka that is the largest and the most active cluster of subduction volcanoes in the world and features the systematic occurrence of deep seismo-volcanic activity.The proposed research will be based on the analysis of two major datasets that perfectly complement each other. First, we will use the data of a large joint German-French-Russian field experiment KISS when more than 80 broadband seismographs operated in the KVG region in 2015-2016 (Shapiro et al., 2017a) and recorded the 2016 Klyuchevskoy eruption including the preparatory phase with unprecedented spatial coverage. We will combine this with the long-term records (partly > 20 years) of the permanent seismic network operated on KVG by our Russian partners, composed today of 25 stations. This dataset contains records of more than 30 strong eruptions (VEI up to 4) of the three major KVG volcanoes: Klyuchevskoy, Bezymiammy, and Tolbachik with most of them being preceded by the deep seismo-volcanic activity.We will analyze the available data with modern seismological methods including time-lapse noise- and earthquake-based monitoring, and measurements of time-variable seismic anisotropy. The results of these investigations will reflect the activity in the plumbing system and its influence on the mechanical properties of the crust. They will be used to constrain and quantify the underlying physical processes based on geophysical fluid dynamics models of viscous flow in porous media analysed by our collaborators. As main scientific results, we anticipate developing a comprehensive physical model of the processes controlling the magma ascent from the deep parts of magmatic systems towards the surface and a set of seismological methods that can be used to monitor these deep-seated pre-eruptive processes.

• DFG Programme: Research Grants
• International Connection: France
• Co-Investigator: Professor Dr. Torsten Dahm
• Cooperation Partners: Professor Dr. Édouard Kaminski; Professor Dr. Nikolai Shapiro