3D TOMOGRAPHY OF IONOSPHERIC ANOMALIES AFTER THE 2020 TURKEY EARTHQUAKE AND TSUNAMI USING GNSS-TEC

Abstract

Global Navigation Satellite System (GNSS) satellite observations can obtain Total Electron Content (TEC) values in the ionosphere layer. The TEC value is obtained by decreasing the phase difference of the GNSS satellite’s two carrier waves (L-band). The calculation of the TEC value using GNSS can be used in disaster phenomena such as earthquakes observed in this study. The earthquake phenomenon can cause vertical deformation in the Earth’s crust, resulting in the appearance of acoustic waves propagating towards the ionosphere layer and changes in the ionosphere density in a moment. A propagating gravity wave has a speed of 0.3 km/ s towards the ionosphere layer. This disturbed ionosphere layer was detected within minutes of the mainshock. The anomaly in this study was detected by Global Positioning System (GPS) Pseudo Random Noise (PRN) 16 from 16 observation GNSS stations on the mainland of Turkey. The observed ionosphere anomalies were then modeled using tomography modelling to obtain spatial information from these anomalies. The tomography results found that the PRN 16 GPS satellites contained positive and negative anomalies located northeast of the epicenter.

Keywords

• 3d tomography
• earthquake
• gnss
• total electron content
• turkey earthquake