Fig. 1.From: Detecting ionospheric TEC perturbations caused by natural hazards using a global network of GPS receivers: The Tohoku case studyMeasured and band-pass filtered TEC disturbances at Usuda (USUD) on March 11, 2011. The earthquake and tsunami-generated acoustic and gravity waves are shown around UT 6:00 and subsequent TIDs commencing about 5 hours later.Back to article page