Cross-correlation Coefficients for the Study of Repeating Earthquakes: An Investigation of Two Empirical Assumptions/Conventions in Seismological Interpretation Practice

• Published in: Pure and applied geophysics Vol. 171; no. 3-5; pp. 425 - 437
• Main Authors: Han, Libo, Wu, Zhongliang, Li, Yutong, Jiang, Changsheng
• Format: Journal Article
• Language: English
• Published: Basel Springer Basel 01.03.2014; Springer Nature B.V
• Subjects: Bandpass filters; Conventions; Correlation analysis; Correlation coefficient; Earth and Environmental Science; Earth Sciences; Earthquakes; Empirical analysis; Frequency bands; Geophysics/Geodesy; Heterogeneity; Mathematical models; Seismic activity; Seismic phenomena; Seismograms; Seismology; Separation; Band Pass Filter; Event Pair; Synthetic Seismogram; Ground Motion; Source Time Function
• ISSN: 0033-4553; 1420-9136
• DOI: 10.1007/s00024-012-0515-3

For the identification and analysis of ‘repeating earthquakes,’ there are two empirical concepts. The first is the assumption that the cross-correlation coefficient of the filtered seismograms of closely spaced ‘repeaters’ depends exponentially on the inter-event separation distance. The second is the convention that in processing regional seismograms, a 0.5–5.0-Hz band pass filter is used. In this article, using a simple layered structure model, we investigated the cross-correlation coefficient of the filtered synthetic seismograms of two closely located events, that is, a ‘doublet.’ We investigated the relation between the cross-correlation coefficient and the inter-event separation distance. Simulation shows that in the 0.5–5.0-Hz frequency band, even if for simple synthetic seismograms without considering lateral heterogeneity or scattering, the exponential dependence is only a first order approximation concept. To check the frequency dependence of the cross-correlation coefficient, we analyzed a group of seismograms of a ‘multiplet’ in Xiuyan, Liaoning, northeast China, recorded by the Regional Seismographic Network of Liaoning Province. The cross-correlation coefficients were observed to be relatively stable against frequency for the 0.5–5.0-Hz frequency band.