The present paper reports the modification in GPS TEC (total electron content) and atmospheric refractivity prior to the Iran earthquake that had occurred on 16 April 2013 in Iran (28.10˚N, 62.05˚E). The analysis of GPS-based TEC from two GPS receivers, Surat (21.16˚N, 72.78˚E) and Lucknow (26.91˚N, 80.95˚E ) and results of atmospheric refractivity profile for radiosonde observation stations (Shiraz, Iran and Delhi, India) around the fault line are presented in this paper. It is seen that atmospheric refractivity gets modified from 8 to 6 days prior to the earthquake at Shiraz, Iran and Delhi, India. The GPS TEC showed variations a few days prior to the earthquake. We conclude that in search of precursory signatures for an earthquake, both GPS TEC and refractivity are important parameters.
P. Karia, S., N. Pathak, K., S. Yadav, K., P. Chaudhary, N., & C. Patel. Ranjan Jana, N. (2014). Modification in Atmospheric Refractivity and GPS Based TEC as Earthquake Precursors. Positioning, 05(02), 46–52. https://doi.org/10.4236/pos.2014.52006