Seismic Monitoring in Mines

by A.J. Mendecki (Editor)

Overview

Routine seismic monitoring in mines was introduced over 30 years ago with two main objectives in mind: • immediate location of larger seIsmIC events to guide rescue operations; • prediction of large rockmass instabilities. The first objective was achieved fairly quickly, but with the subsequent development of mine communication systems, its strategic importance has diminished. The very limited success with prediction can, at least partially, be attributed to three factors: • seismic monitoring systems based on analogue technology that provided noisy and, frequently, poorly calibrated data of limited dynamic range; • the non-quantitative description of a seismic event by at best its local magnitude; and • the resultant non-quantitative analysis of seismicity, frequently through parameters of some statistical distributions, with a somewhat loose but imaginative physical interpretation. The introduction of modern digital seismic systems to mines and progress in the theory and methods of quantitative seismology have enabled the implementation of realtime seismic monitoring as a management tool, quantifying rockmass response to mining and achieving the first tangible results with prediction. A seismic event, being a sudden inelastic deformation within the rockmass, can now routinely be quantified in terms of seismic moment, its tensor, and radiated seismic energy, so that the overall size of, and stress released at, the seismic source can be estimated.

Product Details

ISBN-13:	9780412753008
Publisher:	Springer Netherlands
Publication date:	12/31/1996
Edition description:	1997
Pages:	262
Product dimensions:	0.00(w) x 0.00(h) x 0.39(d)

Table of Contents

1. Seismic transducers.- 1.1 Requirements imposed by ground motion.- 1.2 Theory of inertial sensor operation.- 1.3 Realizable sensor characteristics.- 1.4 Network considerations.- 1.5 Sensor orientation.- 2. Seismic monitoring systems.- 2.1 Signal conditioning.- 2.2 Triggering and validation.- 2.3 Digital data communications.- 2.4 Association.- 2.5 Central processing site.- 2.6 System Performance.- 3. Deconvolution, polarization and wavelet transform of seismic signals.- 3.1 Deconvolution.- 3.2 Polarisation.- 3.3 Wavelet transform.- 4. Seismic raytracing.- 4.1 Shooting and bending.- 4.2 Point-to-curve.- 4.3 Finite difference.- 4.4 Wavefront construction methods.- 5. Location of seismic events.- 5.1 Location by arrival times and/or directions or azimuths.- 5.2 Relative location and similarity of waveforms.- 5.3 Joint hypocentre and velocity determination for clusters of events.- 5.4 Optimal spatial distribution of seismic stations.- 6. Seismic velocity inversion from microseismic data.- 6.1 Seismic tomography.- 6.2 Arrival-time inversion.- 6.3 Application.- 6.4 Velocity inversion in a combined seismological and geomechanical investigation.- 7. Seismic source radiation and moment tensor in the time domain.- 7.1 Radiation from the seismic source — far, intermediate and near fields.- 7.2 Moment tensor.- 8. Spectral analysis and seismic source parameters.- 8.1 Fast Fourier transform and multitaper.- 8.2 Source parameters from spectra.- 9. Nonlinear dynamics of seismic flow of rock.- 9.1 Phase space.- 9.2 Reconstruction of the phase space from seismic data.- 9.3 Fractal correlation dimension.- 9.4 Numerical results.- 9.5 Lyapunov exponent and limits of predictability.- 10. Quantitative seismology and rockmass stability.- 10.1 Quantitative description of a seismic event.-10.2 Quantitative description of seismicity.- 10.3 Nucleation of instability and time to failure.- 11. Application of quantitative seismology in mines.- 11.1 Introduction.- 11.2 Benchmark case studies.- References.

Editorial Reviews

Geophysicists and geotechnical engineers describe recent developments in the field of quantitative monitoring and interpretation of seismic activity in mines. The emphasis throughout is on practical application to real problems, and in particular, the parameters which describe seismic sources; another aim is to bridge the gap between seismologists and rock mechanic practitioners. Discussion includes sensors, data acquisition, signal processing, seismological analysis, quantification of the seismic response of the rockmass to mining, and interpretation in terms of the potential for instability. Annotation c. by Book News, Inc., Portland, Or.

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