Lithospheric deformation and associated manifestation in Ionosphere using GNSS observations

Abstract

newline Abstract newlineThe thesis entitled Lithospheric deformation and associated manifestation in Ionosphere newlineusing GNSS observations focused on the study of earthquake induced ionospheric perturbation newlineusing the Global Positioning System (GPS). In this thesis, a novel method has been developed newlineto estimate the detection altitude of the seismic induced ionospheric variations which newlineis measured using the GPS -Total Electron Content (TEC). The GPS-TEC techniques is well newlineknown in terms of its temporal and spatial coverage. However, due to the integrated nature newlineof the TEC estimated using the GPS technique, the altitudinal information of the Co-seismic newlineIonospheric Perturbation (CIPs) could not determine so far. This limitation has analysed in newlinethe thesis focusing on the early detection of CIP observed during the Mw 7.4 Sanriku- Oki newlineTohoku foreshock. Using simple 3D modelling of acoustic ray traces and its interaction with newlinethe GPS satellite Line Of Sight (LOS) a method has been developed to estimate the detection newlinealtitude of the observed CIPs. From this study it is revealed that the reason for the observed newlineearly arrivals of CIPs is due to the detection of CIPs at lower ionospheric altitudes than the newlineassumed maximum electron density altitude (generally known as hmF2). Further, the proposed newlinemethod is validated by reconstructing the CIP signatures for a moving satellite in the newlinepresence of magnetic and#64257;eld. The synthetic CIP waveforms well correlated with the observed newlineonset time of the ionospheric signatures and the estimated detection altitude. newlineThis proposed method is further applied to an extend seismic source varying simultaneously newlinein space and time during the Mw 9.1 11 March 2011 Tohoku earthquake. In this study newlinethe detection altitude of the CIPs could estimate successfully and also, the individual seismic newlinesources responsible behind the generation of CIPs observed during and#64257;rst 60 s of the seismic newlinerupture has demarcated. The tsunami water excitation simulated over the fault region made newlinethe base of the entire analysis. Moreov