Fig. 4
From: Near-field TEC response to the main shock of the 2008 Wenchuan earthquake
(a) The distribution of maximum amplitude dI(t)max on corresponding direction azimuth from epicenter to SIPs, obtained for all used GPS sites (86 SIPs); maximal response to the main shock was registered in southeast sector. Gray line marks the direction diagram dI(t)max(α). (b) Corresponding distribution of amplitude dI(t)max on distance D from epicenter along the great circle arc only for the southeast sector (40 SIPs).