Investigation the effects of earthquake in Golcuk-Izmit (17 Aug 1999) by using GPS

The North Anatolian Fault Zone (NAFZ), which produced the 1999 Golcuk-Izmit earthquake, extends in three branches in the Marmara Region and causes a significant earthquake hazard. This study consists of processing and analysing data from three stations (TUBI, MER1 and DUMT) that are part of the IGS and MAGNET (Marmara Permanent GPS Network) network and are situated close to the epicentre of the Golcuk-Izmit earthquake. By analysing the time series generated from three daily solutions (TUBI, DUMT and MER1 stations), the displacements due to the earthquake were computed (17 August 1999). When GPS processing on 15–16 August 1999, especially for the Golcuk-Izmit earthquake, is examined, it is possible to interpret this situation as a precursor of the earthquake, as a result of the examination of the data obtained from the process of 15 and 16 August 1999. On August 17, 1999, the movement at the TUBI, DUMT and MER1 points before the earthquake was 2–6 cm while it was computed on average 38–86 cm during and after the earthquake. The earthquake clearly had substantial impact on the horizontal components on 17 Aug 1999. The horizontal coordinates of TUBI, DUMT and MER1 stations have changed by around 49–87 cm, and the height components have changes by around 14–137.10 cm based on the time series of coordinate discrepancies.