TEC anomalies assessment for earthquakes precursors in North-Eastern India and adjoining region using GPS data acquired during 2012-2018

摘要

A total of 160 earthquakes in North East Indian region and surroundings were analysed for earthquake precursor detection using GPS based Total Electron Content (TEC) estimation in the Ionosphere. TEC is very sensitive to short-term disturbances of a geomagnetic storm, solar flares and seismic activities. In the present study, TEC in the ionosphere was measured using dual-frequency signals from five GPS-based continuously operating reference stations/system (CORS) installed in North Eastern states of India. The abnormality in TEC variations was observed by constructing boundary limits using statistical method, the values crossing the limits being the anomaly. The results for M-w 5 earthquakes could be 46.50% detectable, M-w 5.6 could be 81.56% detectable and M-w 6 earthquakes could be fully detectable. Rate of success with reference to CORS as computed, is found in the order of Cherrapunjee, Meghalaya Madankamdev, Assam Mohanpur, Agartala Mawtawar, Meghalaya Khanapara, Assam. Therefore present investigations confirmed TEC anomalies prior to earthquakes with good rate of success, making it imperative to set up an automated system for real-time monitoring of TEC for Earthquake precursor detection and appropriate forewarning in near future.