Using Dynamic Fourier Analysis to Discriminate Between Seismic Signals from Natural Earthquakes and Mining Explosions

<abstract> <p>A sequence of intraplate earthquakes occurred in Arizona at the same location where mining explosions were carried out in previous years. The explosions and some of the earthquakes generated very similar seismic signals. In this study Dynamic Fourier Analysis is used for discriminating signals originating from natural earthquakes and mining explosions. Frequency analysis of seismograms recorded at regional distances shows that compared with the mining explosions the earthquake signals have larger amplitudes in the frequency interval ~ 6 to 8 Hz and significantly smaller amplitudes in the frequency interval ~ 2 to 4 Hz. This type of analysis permits identifying characteristics in the seismograms frequency yielding to detect potentially risky seismic events.</p> </abstract>

Evaluation of Human Comfort under Repeated Intermission Vibrations

Mining explosions and railway transportation generally result repeated intermission vibrations (RIV). These vibrations, with relatively shorter duration and larger peak acceleration, often repeat several times in a day. A proper evaluation method of human response should consider both the non-stationary nature and the occurrence frequency of RIV. This result the evaluation process has some differences compared with that for ordinary stationary vibration. Current evaluation method for human vibration comfort is first reviewed in this paper. Then the vibration dose value (VDV) and frequency of vibration events are introduced to evaluate vibration comfort under RIV. At last part of the paper, two vibration cases, one for blasting and one for railway transportation, are analyzed to explain above evaluation process.