Fig. 3.
From: Detection of seismic events triggered by P-waves from the 2011 Tohoku-Oki earthquake
P-wave spectral ratios of the Mw 9.0 Tohoku-Oki earthquake compared with the Mw 6.1 reference earthquake over the main Japanese Islands. The spectral ratio is averaged between 0.5 and 2 Hz. Also shown are the Centroid Moment Tensor (CMT) solutions of the two earthquakes (Nettles et al., 2011). The star represents the hypocenter of the Tohoku-Oki earthquake, from the JMA catalogue. The filled circles indicate the epicenters of triggered NVT. 638 Hi-net stations used are shown by open circles.