Detection of iono-seismic signatures of the nepal earthquake using COSMIC RO measurements

Iono-seismic anomaly detection is challenging task for understanding the lithosphere-atmosphere-ionosphere coupling mechanism during earthquakes and tsunami events. To understand the interaction of atmospheric gravity waves with ionospheric Total Electron Content (TEC) variations, Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) Radio occultation (RO) measurements are considered for the analysis. In this paper, iono-seismic features are extracted using the Complementary Ensemble Empirical Mode Decomposition — Multifractal Detrended Fluctuation Analysis (CEEMD-MFDFA) technique. The Radio Occultation-TEC data of the Nepal earthquake (2015) is investigated, and it is found that the CEEMD-MFDFA technique provided wave features of the TEC signals. It is evident from the negative values below −0.5 of Hurst exponent values that the first three intrinsic mode functions (IMF) during the Nepal earthquake represented the iono-seismic anomalies. It is also observed that the iono-seismic features are occupying the vertical wavelength range because of sounding line is scanning vertically the atmosphere and above 50 mhz to 0.28hz are observed during the Nepal earthquake. The outcome of this work would be extremely useful for understanding the coupling mechanism of earthquake-ionosphere phenomena.