The vibrations caused by the songs “Love Story” and “Shake it Off” during the Taylor Swift concerts in July could be measured throughout the tunnel of the European XFEL X-ray laser, which ends more than three kilometers away from the Volksparkstation in Schenefeld. The 19-kilometre fiber optic network of Science City Hamburg Bahrenfeld, which the “WAVE” research network uses as a seismic sensor, and the “PETRA III” accelerator at the German Electron Synchrotron DESY also provided extensive recording data throughout the concert. The measurements were transmitted via livestream.

However, this was not just for the entertainment of the fans: “Of course, it is a great opportunity to make our research accessible to a wider audience and to show how dynamic our subsurface is,” explains Prof. Dr. Céline Hadziioannou, Professor of Seismology at Universität Hamburg (UHH). However, the results were also used specifically for research. “The songs emitted different seismic signals. This helps us to understand, for example, what triggers them, i.e. the bass of the music or the jumping of the audience,” says Prof. Dr. Katharina-Sophie Isleif, Professor of Measurement Technology at Helmut Schmidt University and member of the Quantum Universe (QU) Cluster of Excellence at UHH.

Improving measuring instruments and understanding movements of waves

The paths that the waves take from their point of origin are also very illuminating. A wide variety of events are therefore recorded. After Taylor Swift, singer Robbie Williams and the band Deichkind have already been guests in the research team's livestream with their performances at the Trabrennbahn. Justin Timberlake will follow on September 4 and the Scorpions on September 13 - both at the Barclays Arena. In addition, numerous HSV home soccer matches will be broadcast, and heavy thunderstorms will also be included in the analyses.

On the one hand, the results can be used to further refine and improve the measurement network. On the other hand, by understanding the waves and their propagation, changes in temperature or soil moisture underground can be determined in future. This enables statements to be made about the influence of climate change on the city. The findings are also important for research into gravitational waves, which is being carried out in the QU Cluster of Excellence, among others.

As the experiments for detecting these cosmic signals are extremely sensitive to vibrations of all kinds, it is essential to precisely measure and predict possible disturbing waves. Seismic networks such as “WAVE” should help to reduce this so-called Newtonian noise in the future. “We are training ourselves and the network with the concerts and soccer matches to enable groundbreaking physical discoveries,” says Prof. Dr. Oliver Gerberding, Professor of Gravitational Wave Detection at the University of Hamburg.

An interdisciplinary cooperation

“WAVE” is coordinated by Prof. Hadziioannou and Prof. Gerberding from the University of Hamburg, Prof. Isleif from the Helmut Schmidt University and Dr. Holger Schlarb from DESY. Researchers from the European XFEL and the German Research Center for Geosciences Potsdam will also be taking part. The livestreams can be accessed via the network's website.