Seismic interferometry with antipodal station pairs

Abstract

In this study, we analyze continuous data from all Global Seismographic Network stations between year 2000 and 2009 and demonstrate that several body wave phases (e.g., PP, PcPPKP, SKSP, and PPS) propagating between nearly antipodal station pairs can be clearly observed without array stacking using the noise/coda cross-correlation method. Based on temporal correlations with global seismicity, we show that the observed body waves are clearly earthquake related. Moreover, based on single-earthquake analysis, we show that the earthquake coda energy observed between ∼10,000 and 30,000 s after a large earthquake contributes the majority of the signal. We refine our method based on these observations and show that the signal can be significantly improved by selecting only earthquake coda times. With our improved processing, the PKIKP phase, which does not benefit from the focusing effect near the antipode, can now also clearly be observed for long-distance station pairs. Key Points Near-antipodal body waves can be extracted using seismic interferometry The earthquake coda energy is important for the seismic interferometry to work The coda interferometry improves the SNR of the observed body waves ©2013. American Geophysical Union. All Rights Reserved.