Determination of velocity field and strain accumulation of densification network in Marmara Region

Abstract

For the implementation of constructing continuously operating reference stations and determination of transformation parameters, Turkey has started a new project: Turkish Continuously Operating Reference Stations (CORS-TR). Network-120, Network-90, and Network-60 were created as CORS test networks. These networks were composed of 115 check points which were established by institutions such as Geodesy Department of Kandilli Observatory and Emihquake Research Institute of Bogazic;i University, Istanbul Metropolitan Municipality, General Command of Mapping (GCM), General Directorate of Land Registry and Cadastre, and TUB IT AK Marmara Research Center (MRC) in KIrklareli, Tekirdag, Bursa, Bilecik, and Adapazan. Before the 1999 earthquake, positions of 115 check points which are tied to Turkish National Fundamental GPS Network (TNFGN) were determined by different time and institutions. Between July 15 and October 30, 2006; corporations such as TOPCON, TRIMBLE, and LEICA made observations. They evaluated CORS test networks. TOPCON and TRIMBLE measured all of CORS test networks, but LEICA measured only Network-60. Positions of main points of test networks were calculated and points were tied to International GNSS Service (lGS). The purpose of this study is to provide analysis of datum of 1999 observations and unity of datum, to analyze evaluation and computation of coordinates of 2006 observations, and to examine unity of datum in 2006 observations. It will also describe the determination of velocity field, strain accumulation on test field by modeling difference vectors between the coordinates of check points and the comparisons with other studies. The difference vector between the coordinates of check points in 1999 and 2006 (observed and computed by different companies) were derived.