Fig. 3
From: Near-field TEC response to the main shock of the 2008 Wenchuan earthquake
(a) Criterion function C(V) for the plane (solid line) and spherical (dotted line) wave front approximations. (b) 2D function C(α, V) for the plane wave front model; thin horizontal line mark cross section of C(α, V) corresponding to the dependence C(V) for the plane wave form shown in panel (a). Maximum value C(α, V)max of about 0.8 (marked by cross) corresponds the values of velocity V = 560 m/s and azimuth α = 160° of the wave front propagation.