Client

Civil Engineering Office, Canton of Schaffhausen

Office for Waste, Water, Energy and Air (AWEL), Canton of Zurich Building Department

Geological Office

Dr. von Moos AG

Services Provided

• Periodic repeat measurements with portable seismometers.
• Feasibility study for long-term monitoring of the Rhine Falls rock using modal analysis (resonance frequency and natural oscillation directions).
• Evaluation of the influence of environmental factors on the vibrational characteristics.
• Digitization and evaluation of analog seismograms from 1981.

Project Description

The Rhine Falls, the largest waterfall in Europe and a popular tourist destination in Switzerland, is home to a striking rock tower at its center that is visited by numerous tourists every day.

With the aim of being able to quantitatively assess the stability of the tower, we investigated the potential of passive seismics for long-term monitoring of the Rhine Falls rock. We were able to identify clear resonance frequencies and corresponding natural modes of vibration, which have remained almost constant over the last few decades. The investigation also showed that environmental influences such as temperature and discharge rates have a small influence on the vibrational properties of the Rhine Falls rock. These results show that periodic passive seismic repeat measurements are a suitable tool for quantitative long-term monitoring of the Rhine Falls, as a significant decrease in resonance frequencies would indicate structural damage to the rock tower.

News Report in «SRF Tagesschau»