Combination of Principal Component Analysis and Time-Frequency Representation for P-Wave Arrival Detection

Jacek Wodecki,Agnieszka Wyłomańska,Adam Mirek,Justyna Hebda-Sobkowicz,Radosław Zimroz

doi:10.1155/2019/5961073

Abstract

Seismic events are phenomena which commonly occur in the mining industry. Due to their dangerous character, such information as the energy of the potential event, the location of hazardous regions with higher seismic activity is considered valuable. However, the acquisition of this information is almost impossible without the ability to detect the onset time of the seismic event. The main objectives of algorithms in finding P-wave are high accuracy, reasonable time of operation, and automatic detection of wave arrival. In this paper, an innovative method which incorporates principal component analysis (PCA) with time-frequency representation of the signal is proposed. Due to the significant difference between the spectra of recorded seismic wave and pure noise which precedes the event, time-frequency representation allows for better accuracy of signal change detection. However, with an additional domain, the complexity rises. Thus, the incorporation of PCA (which is known for high efficiency in lowering data dimensions while maintaining original information) seems to be recommended. In order to show the feasibility of the method, it will be tested on real data originating from monitoring system used in underground mine.

Highlights

Analysis of mining-induced seismic events, prediction of such events, their evaluation in sense of mechanism, location, and amplitude identification are crucial in the underground mining industry
Most of the information is focused on principal component 1 (PC1)
It means that the spectrogram is redundant, and there is no need to detect P-wave arrival time for each subsignal of the spectrogram; there is only need to analyse the first PCs which handle the most significant information

Summary

Introduction

Analysis of mining-induced seismic events, prediction of such events, their evaluation in sense of mechanism, location, and amplitude (energy) identification are crucial in the underground mining industry. P-wave detection is essential in calculating the energy of the event, description of the event, focal mechanism [1], and so on. E time of seismic wave arrival can be acquired manually by specialists from seismic station in the mine or automatically by previously developed algorithms. E problem of P-wave detection might be solved in many ways. These two approaches differ in terms of time consumption and accuracy, as human work is slower but more precise. As the specialists may face hundreds of events daily, the utilization of algorithms seems indispensable. e preliminary usage of some algorithms followed by a manual improvement became a common habit in seismic stations

Methods

Results

Conclusion