Register      Login
Exploration Geophysics Exploration Geophysics Society
Journal of the Australian Society of Exploration Geophysicists
RESEARCH ARTICLE (Open Access)

Time–quefrency analysis of overlapping similar microseismic events

Koji Nagano
+ Author Affiliations
- Author Affiliations

Muroran Institute of Technology, Mizumoto 27-1, Muroran, Hokkaido 050-8585, Japan. Email: nagano@mmm.muroran-it.ac.jp

Exploration Geophysics 47(2) 133-144 https://doi.org/10.1071/EG15033
Submitted: 15 April 2015  Accepted: 18 April 2015   Published: 15 May 2015
Originally submitted to SEGJ 29 December 2013, accepted 7 January 2015  

Journal Compilation © ASEG 2016

Abstract

In this paper, I describe a new technique to determine the interval between P-waves in similar, overlapping microseismic events. The similar microseismic events that occur with overlapping waveforms are called ‘proximate microseismic doublets’ herein. Proximate microseismic doublets had been discarded in previous studies because we had not noticed their usefulness. Analysis of similar events can show relative locations of sources between them. Analysis of proximate microseismic doublets can provide more precise relative source locations because variation in the velocity structure has little influence on their relative travel times. It is necessary to measure the interval between the P-waves in the proximate microseismic doublets to determine their relative source locations.

A ‘proximate microseismic doublet’ is a pair of microseismic events in which the second event arrives before the attenuation of the first event. Cepstrum analysis can provide the interval even though the second event overlaps the first event. However, a cepstrum of a proximate microseismic doublet generally has two peaks, one representing the interval between the arrivals of the two P-waves, and the other representing the interval between the arrivals of the two S-waves. It is therefore difficult to determine the peak that represents the P-wave interval from the cepstrum alone. I used window functions in cepstrum analysis to isolate the first and second P-waves and to suppress the second S-wave. I change the length of the window function and calculate the cepstrum for each window length. The result is represented in a three-dimensional contour plot of length–quefrency–cepstrum data. The contour plot allows me to identify the cepstrum peak that represents the P-wave interval. The precise quefrency can be determined from a two-dimensional quefrency–cepstrum graph, provided that the length of the window is appropriately chosen. I have used both synthetic and field data to demonstrate that this method can be used to identify the cepstrum peak that represents the interval between the arrivals of successive P-waves.

Key words: cepstrum, microseismic events, quefrency, similar events.


References

Block, L. V., Cheng, C. H., Fehler, M. C., and Phillipe, W. S., 1994, Seismic imaging using microearthquakes induced by hydraulic fracturing: Geophysics, 59, 102–112

Bogert, B. P., Healy, M. J., and Tukey, J. W., 1963, The quefrency analysis of time series for echoes: cepstrum, pseudo-autocovariance, cross-cepstrum, and saphe cracking, in M. Rosenblatt, ed., Time series analysis: Wiley, 209–243.

Brockwell, P. J., and Davis, R. A., 2002, Introduction to time series and forecasting: Springer-Verlag.

Cao, A., and Romanowicz, R., 2007, Locating scatterers in the mantle using array analysis of PKP recursors from an earthquake doublet: Earth and Planetary Science Letters, 255, 22–31
Locating scatterers in the mantle using array analysis of PKP recursors from an earthquake doublet:Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD2sXhvVGgtL0%3D&md5=07b242b870935cf2a72214e8e1b4e802CAS |

Childers, D. G., Skinner, D. P., and Kemerait, R. C., 1977, The cepstrum: a guide to processing Proceedings of the IEEE, 65, 1428–1443
The cepstrum: a guide to processingCrossref | GoogleScholarGoogle Scholar |

Danesi, S., Bannister, S., and Morelli, A., 2007, Repeating earthquakes from rupture of an asperity under an Antarctic outlet glacier: Earth and Planetary Science Letters, 253, 151–158
Repeating earthquakes from rupture of an asperity under an Antarctic outlet glacier:Crossref | GoogleScholarGoogle Scholar | 1:CAS:528:DC%2BD28XhtlCkt7vF&md5=1728db8a78c7c0b2da082a047123728eCAS |

Eisner, L., Fischer, T., and Le Calvez, J. H., 2006, Detection of repeated hydraulic fracturing (out-of zone growth) by microseismic monitoring: The Leading Edge, 25, 548–554
Detection of repeated hydraulic fracturing (out-of zone growth) by microseismic monitoring:Crossref | GoogleScholarGoogle Scholar |

Ito, A., 1985, High resolution relative hypocenters of similar earthquakes by cross-spectral analysis method: Journal of Physics of the Earth, 33, 279–294
High resolution relative hypocenters of similar earthquakes by cross-spectral analysis method:Crossref | GoogleScholarGoogle Scholar |

Moriya, H., Nakazato, K., Niitsuma, H., and Baria, R., 2002, Detailed fracture system of the Soultz-sous-Forêts HDR field evaluated using microseismic multiplet analysis: Pure and Applied Geophysics, 159, 517–541
Detailed fracture system of the Soultz-sous-Forêts HDR field evaluated using microseismic multiplet analysis:Crossref | GoogleScholarGoogle Scholar |

Nagano, K., and Ehara, D., 2008, Automatic detection of proximity AE doublets for relative location of subsurface fracture reservoir: Institute of Electrical Engineers of Japan Transactions on Electronics, Information and Systems, 128, 1005–1010

Percival, D. B., and Walden, A. T., 1998, Spectral analysis for physical applications: Cambridge University Press.

Phillips, W. S., 2000, Precise microearthquake locations and fluid flow in the geothermal reservoir at Soultz-sous-Forêts, France: Bulletin of the Seismological Society of America, 90, 212–228
Precise microearthquake locations and fluid flow in the geothermal reservoir at Soultz-sous-Forêts, France:Crossref | GoogleScholarGoogle Scholar |

Poupinet, G., Ellsworth, W. L., and Frechet, J., 1984, Monitoring velocity variations in the crust using earthquake doublets: an application to the Calaveras fault, California: Journal of Geophysical Research, 89, 5719–5731
Monitoring velocity variations in the crust using earthquake doublets: an application to the Calaveras fault, California:Crossref | GoogleScholarGoogle Scholar |

Poupinet, G., Ratdomopurbo, A., and Coutant, O., 1996, On the use of earthquake multiplets to study fractures and the temporal evolution of an active volcano: Annali di Geofisica, 39, 253–264

Rutledge, J. T., and Phillips, W. S., 2003, Hydraulic stimulation of natural fractures as revealed by induced microearthquakes, Carthage Cotton Valley gas field, east Texas: Geophysics, 68, 441–452
Hydraulic stimulation of natural fractures as revealed by induced microearthquakes, Carthage Cotton Valley gas field, east Texas:Crossref | GoogleScholarGoogle Scholar |

Rutledge, J. T., Phillips, W. S., and Mayerhofer, M. J., 2004, Faulting induced by forced fluid injection and fluid flow forced by faulting: an interpretation of hydraulic-fracture microseismicity, Carthage Cotton Valley gas field, Texas: Bulletin of the Seismological Society of America, 94, 1817–1830
Faulting induced by forced fluid injection and fluid flow forced by faulting: an interpretation of hydraulic-fracture microseismicity, Carthage Cotton Valley gas field, Texas:Crossref | GoogleScholarGoogle Scholar |

Yamawaki, T., Nishimura, T., and Hamaguchi, H., 2004, Temporal change of seismic structure around Iwate volcano inferred from waveform correlation analysis of similar earthquakes: Geophysical Research Letters, 31, L24616
Temporal change of seismic structure around Iwate volcano inferred from waveform correlation analysis of similar earthquakes:Crossref | GoogleScholarGoogle Scholar |