UNcovering the role of Pyroclasts on volcanIc jet Noise – UNPIN

• Applicant: Dr. Ulrich Küppers, since 9/2022
• Subject Area: Geophysics
• Term: from 2019 to 2024
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 419092521

During explosive volcanic eruptions, magma is fragmented and ejected as tephra. The energy required for driving an explosive eruption depends on a variable combination of intrinsic (e.g., outgassing of volatiles dissolved in magma) and extrinsic (e.g., evaporation of external water) processes. Tephra in the atmosphere can pose significant and varied hazards to society and infrastructures. The timing and the intensity of an eruption are not, or only insufficiently, foreseeable, and yet predictions ahead of time are essential to assess and mitigate volcanic hazards.Volcanic activity can be monitored directly on site as well as remotely, e.g. via space-based systems or earth-based seismic and acoustic networks. In particular, acoustic signals are increasingly used for monitoring active volcanoes in remote areas. Volcanoes emit acoustic signals in both the audible and the infrasonic spectral range. The goal of acoustic monitoring is to relate a measured acoustic signal with the specific eruption process. However, the interpretation of these signals is still difficult, because the underlying physics, developed for the flow of pure air, ignore the complex reality of volcanic environments. To date, there are no comprehensive datasets explaining the influence of volcano-relevant conditions on the acoustic signals.The aim of this project is to determine the influence of volcano-specific dynamic conditions on the measurable acoustic signals, in particular:- the presence of (volcanic) particles, and their volume fraction and size;- the volume, pressure, and temperature of the explosion-driving gas;- the geometry of the volcanic vent ("nozzle shape"); and- the morphology of the entire volcanic edifice.For this purpose, scaled, specially designed shock-tube experiments will be performed to simulate impulsive volcanic eruptions ("starting jets"). Acoustic recording of these laboratory experiments will uncover the influence of these parameters on the associated acoustic signals, thus providing unique insights into the dynamics of particle-laden jets and their acoustic properties. The scaled and reproducible laboratory experiments will then be compared with the analysis of volcanic eruptions. The results will open new doors to our capacity to interpret the acoustic signals generated during explosive volcanic eruptions, contributing significantly to an improved eruption characterization and ensuing risk assessment and the related resilience of people and society to active volcanoes.

• DFG Programme: Research Grants
• International Connection: Italy
• Co-Investigators: Professor Dr. Donald Bruce Dingwell; Dr.-Ing. Juan José Peña Fernández; Professor Dr. Jörn Lothar Sesterhenn
• Cooperation Partner: Dr. Jacopo Taddeucci
• Ehemalige Antragstellerin: Dr. Valeria Cigala, until 8/2022