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Enhancement of the Strong Motion and Seismic Network in Turkey
SfP-Seismic Assessment 977484

Objective And Scope

This proposal sets to establish two seismic arrays that will serve as models in Turkey for the future, and to increase the density of instruments in the national strong motion network at selected urban zones. This proposal is limited only to describing a small part of a wider system that will be enhanced mainly through Turkish national resources. The successful initiation of these arrays that will record ground motions from both small- and large-magnitude earthquakes will serve as leverage for similar arrangements at other suitable locations. The arrays will become incorporated into the national system in operation in Turkey, and serve to enhance its utility. A national strong motion arrays council consisting of experts in this field should establish the national objectives, and promote the idea nationally. We plan to form this council quickly so that their counsel is available during the planning and installation stages.

With heightened odds for a renewed major earthquake near the western end of the North Anatolian Fault estimated to affect Istanbul, one of these arrays would be near Yalova, a city 40 km to the southeast, and extend linearly to Bursa, about 65 km to the south-west of Yalova. (The rupture of the 17 August 1999 earthquake did not reach Yalova, but it is reasoned that the next segment to break will include it.) The vicinity of Aydýn-Denizli, 100 km east of Izmir along the Menderes river valley, is considered for the second array. These two locations are in transform and normal fault mechanism regions, respectively. Yalova, Bursa, Izmir, Aydin and Denizli are the candidate cities for deploying instruments to complement the currently existing isolated ones

Among significant objectives is also the training of young seismologists and engineers in the design, installation, and maintenance of these array as well as utilization of the data that may be recorded on them. Most of these younger staff are part of the Earthquake Research Division of the Turkish General Directorate of Disaster Affairs, the national agency responsible for the operation of the national system. Qualified young academicians from METU and ITU will also be trained for strong motion instrumentation and operation. With the US planning to spend $175 million to establish an Advanced National Seismic System that will require $47 million annually to maintain, the global importance of protection of lives and infrastructure against the seismic peril is confirmed. Investment in these instruments may pay off for decades with the knowledge to build safer structures. Large earthquakes that are not properly recorded are irreplaceable, missed opportunities that can result in delays of decades before a similar earthquake is recorded. The practice of risk management in the country will benefit from the information that could be generated from these arrays.