Figure S3. Same as Figure S2 but for a non-earthquake day. (a) Snap shot for T = 4:26 UT (Vertical line) on Feb. 19, 2011 (DOY50). VTEC variation in the circle is supposed to be the cause of the oscillation of C(T) (see text S1). (b) Calculated C(T) using the 31 stations with the central station 0214.