Empirical relocation of large subduction-zone earthquakes via the teleseismic network correlation coefficient method

Abstract

Abstract The network correlation coefficient method is a powerful tool for relocating events under low signal-to-noise ratio conditions, as well as small ($$M_{\text{W}} < 5.0$$ MW<5.0 ) near-field earthquakes, where the relocation is performed by maximizing the sum of the waveform correlation coefficients between pairs of events in the network. Here we extend the method to relocating large ($$6.0 \le M_{\text{W}} \le 7.3$$ 6.0≤MW≤7.3 ) teleseismic subduction-zone events. We apply a source duration correction to better correlate different-magnitude events. Four case studies are presented where we precisely locate interplate events near the rupture areas of giant megathrust earthquakes, namely the 2011 $$M_{\text{W}} \;9.1 \,$$ MW9.1 Tohoku, 2010 $$M_{\text{W}} \;8.8$$ MW8.8 Maule, 2005 $$M_{\text{W}} \; 8.6$$ MW8.6 Nias, and 2007 $$M_{\text{W}} \;8.5$$ MW8.5 Bengkulu earthquakes. We demonstrate the extensive links between these interplate events, with a clear alignment of earthquakes observed along each subduction interface.

Keywords

• Relocation
• Teleseismic
• Cross-correlation
• Network correlation coefficient