A rapid determination network in Turkey: Towards an early warning system in the Marmara Region
Niyazi Turkelli, Ali Pinar, Serafettin Ince
There are two aims for the above projects: a) To monitor seismic activity and tectonic deformation continuously in the Marmara region. Also, to allow the determination of hypocentres in a short time with high accuracy. These projects would be extended to an early warning system in the region. b) To enable scientists to the use advanced methods of studying teleseismic and regional waveform modelling, travel time tomography, hypocentre location inversion, shear wave splitting analysis, seismic risk analysis and forecasting future earthquake locations.
These projects are important for the Marmara region, having 20 million population and 40% of industrial investment of Turkey, and at the same time a great potential for earthquakes. As a result, the Marmara region will be monitored by a network of 13 high quality digital seismographs. The central data acquisition in Istanbul, Kandilli will have real-time data link with the central data acquisition system in the city of Adapazar which monitors the seismic activity in Mudurnu valley. We believe that these two networks will remarkably increase the earthquake dedectibility in the region.
The seismicity in the Marmara region is the result of tectonic movements along three possible westward extensions of the NAFZ beyond the Mudurnu valley where the influence of the Aegean extensional tectonic regime has been recognised (Barka and Kadinsky-Cade, 1988). The number of earthquakes identified in this region for the historical period (AD 1 to 1899) is around 600. Thirty-eight of them are estimated to have been relatively large shocks of magnitude Ms > 7.0 ( Ambraseys and Finkel, 1991). According to Soysal et al., (1981), 124 damaging earthquakes occurred with widespread damages in Istanbul, in places even very serious. The average intensity was about VIII. Many public buildings, mosques and houses were shattered and left on the verge of collapse, while most of the older constructions fell down. Water distribution was disrupted. Deaths are estimated at a few thousand (about 0.3–0.4% of a total population of 900,000). For the instrumental period (after 1900), the earthquake activity in the Marmara Sea region shows typical swarm-type activities.