Effect of Some Major Shallow Earthquakes (M > 6.0, Depth < 30 km) that Occurred in and Around India on the GPS-Based Total Electron Content (TEC) of the Ionosphere

The GPS-based total electron content (TEC) data observed at four low-latitude TEC stations—Lucknow (LCK3), Bangalore (IISC), Hyderabad (HYDE), and Lhasa (LHAZ) are subjected to Quartile-based statistical analysis to study the effect of six major shallow earthquakes (M > 6.0, depth < 30 km) that occurred in and around India in 2017. The results show anomalous enhancements in the TEC data 2–14 days before and 3–15 days after the onset of the earthquakes considered. These pre- and postseismic TEC enhancements are between 1.2–8.7 and 0.7–25.6 TECU, respectively, and percentage TEC enhancements before and after these earthquakes range from 3.82–69.04 and 4.40–95.53