Low frequency vibration and noise generated by seismic sources and their effects on surroundings

摘要

This paper presents some sources of induced seismicity which generate low frequency mechanical and acoustic vibration transmitted through the soil in the ground and through the air on to buildings, industrial structures, machinery and their surroundings, which include human beings. Some sources, as a result of human activity, for strong low frequency vibration and their subsequent seismic waves were investigated and analyzed. These types of vibrations and noise are responsible for the damage of structures, machinery and are an annoyance during relaxation, sleep and mental work, which may reflect negatively on the comfort and health of the population, and the mental state of people. Measurements were made for different deterministic sources and their operating conditions: for example, high power sawmills and an unbalanced rotating component of a dust separators. For detection of the low frequency vibration, the acceleration vibration was measured and the fast Fourier transform (FFT) analysis was used. From the FFT analysis the reasons of the strong low frequency vibration were detected and corresponding measures were designed to reduce this vibration. Low frequency vibration and noise sources are specified, and the direct effects on the structure and surrounding (include people) are investigated as well. The results of the frequency analysis, and the consequent measures shows the most effective way to reduce very strong energy of low frequency loading.