The seismic signature of skiing

In March 2023 the annual winter school SKIENCE (www.skience.de) was held in the Bavaria alps, south-east of Munich. The topic was environmental seismology with a focus on seismic monitoring using ambient seismic noise. The winter school had strong practical training aspects. Prior to the meeting 12 5Hz nodes (SmartSolo) were deployed in the valley near Bayrischzell with the goal to explore local structure and site effects using interferometric methods. During the midweek free afternoon the 12 SmartSolo nodes were installed on both sides of a slalom run with several gates through which participants of the winterschool skied one after each other. First inspection of the data showed that clear signals of the skiers could be identified. Here, we report on attempts to use the seismic data records to recover the tracks of the skiers as moving seismic sources. Questions associated with this experiment are at which points in the tracks seismic energy is generated, where exactly the incoming signals propagate and with what velocities, and how well the source locations can be backprojected. A simple theoretical model is used to develop the inversion tools to recover the moving sources.