A GNSS-based near real time automatic Earth Crust and Atmosphere Monitoring Service for Turkey

Abstract

Turkey is located in a highly active earthquake zone. Many geodynamic and seismic activities occur during a day, such as earthquakes, landslides, sinkholes and creep movements. In addition to seismicity, Turkey has unique physical features like being surrounded by seas on three sides, affected by different climate types. It is located on mid latitudes, which makes Turkey very suitable for atmospheric studies. For this reason, Turkey serves as a natural laboratory for geodesy, geophysical and atmospheric scientists. Therefore, Global Navigation Satellite System (GNSS) data are used in many areas. However, not all the scientists can reach or process the data for coordinate-based studies. Within the scope of the study, a GNSS-based Earth Crust and Atmosphere Monitoring Service is established at the Zonguldak Bulent Ecevit University. Using the results of the GNSS processing, time series of GNSS station positions are produced and used to infer strain solutions related to earthquakes. Estimates of the Precipitable Water Vapour (PWV) and the Total Electron Content (TEC) in the ionosphere are made available for tropospheric and ionospheric studies, respectively. Visualisation of the results are intended to be provided to the scientific community. Results show that the root mean square (RMS) differences of the PWV between GNSS and radiosondes are in the range of 1–3 mm. RMS differences of the TEC is in the range of 2–3 TEC units when comparing our GNSS estimates with the Global Ionospheric Maps (GIM) from the International GNSS Service (IGS). One of the main results obtained from the analysis centre is near real-time strain rates and their relations to actual earthquakes. Results show that near real-time strain rates can be assessed as a precursor parameter for earthquakes.