Measurement of vibrations of the A/2 building at the University of Miskolc by laser interferometric methods

Abstract

Michelson type (LIMA: Laser Interferometric Motion Analyser) and LDV (Laser Doppler Vibrometer) interferometers were used to measure the very week vibrations (less than 1µm amplitude) of the walls of our laser laboratory. We found that the dominant component is a 6-7 Hz vibration, which was identified as the transversal vibration of the whole A/2 building. This vibration cannot be affected by local activity (eg. running and jumping around on the corridor or stairs), but it has a typical daily tendency, and it has a connection with the intensity of the wind, too. The wall vibrations that can be locally excited have quite different frequencies (approx. 2,5 Hz, 30-40 Hz, and approx. 60 Hz).