The effect of GNSS reference station number on determining crustal deformations: a case study for October 23, 2011, Mw 7.1 Van earthquake

This study explores the impact of the selected GNSS reference station numbers on determining horizontal and vertical coseismic deformations resulting from the October 23, 2011, Mw 7.1 Van Earthquake in Eastern Anatolia, near Van city center. Leveraging high-precision Global Navigation Satellite System (GNSS) measurements from 14 CORS-TR (Continuously Operating Reference Stations of Türkiye) stations and utilizing Bernese v5.2 software for data analysis, the research evaluates the effect of datum selection through various reference station configurations on the accuracy of coseismic displacement measurements. Our findings indicate significant variations in RMS values and coseismic displacements across different datum models. The analysis shows that models incorporating eight or more International GNSS Service (IGS) stations in the datum definition yield more stable and consistent results, with variations in displacement measurements not statistically significant when compared to a model using all available (19 station) IGS stations. This underscores the critical importance of datum definition in geodetic measurements for the assessment of natural disasters and emphasizes the need for a comprehensive and precise selection of reference stations number in the geodetic field. The study contributes to the broader geodetic efforts to develop fault slip models and improve the understanding of seismic events’ impact on Earth’s surface.