Fig. 1.
From: High-frequency rupture properties of the Mw 9.0 off the Pacific coast of Tohoku Earthquake
Distribution of stations in North America used in the back-projection analysis of the Mw 9.0 March 11 mainshock and Mw 7.1 April 7 aftershock. Green triangles show 453 stations that contributed to low-frequency analysis, and red triangles show 433 stations that are used for high-frequency analysis. Note that stations that are more than 92 degrees from the April 7 aftershock location are not included, as well as seismograms with correlation values less than 0.7 (Ishii et al., 2005).