Turkey

	Earthquake

Turkey Earthquake

A significant proportion of Turkey is subject to frequent and damaging earthquakes. Turkey is located on the relatively small Anatolian plate, which is squeezed between three other major tectonic plates—the north-moving African and Arabian plates located to the south, and the south-moving Eurasian plate located to the north. The combination of these plate movements is forcing the Anatolian plate to move west into the Aegean Sea. This movement produces fault structures at the boundary between the plates, most significantly the North Anatolian Fault Zone (NAFZ).

The NAFZ is a right lateral strike-slip type fault zone that stretches 1,500 km (930 miles) across Turkey and has been the source of eight earthquakes of magnitude 7 or greater in the last century (compared to two for the San Andreas fault in California). Starting with the 1939 Erzincan Earthquake (Mw7.9), the NAFZ had a westward migrating sequence of earthquakes, the most recent being the 1999 Kocaeli and Duzce Earthquakes.

Of particular interest is the quantification of earthquake hazard around the Marmara Sea, a region that accounts for 60% of the insured earthquake exposure in Turkey, and includes Istanbul and other major urban zones such as Bursa, Yalova, and Izmit. Modeling the hazard potential in the Marmara Sea region is more complex and uncertain than the rest of the country, because a significant portion of the NAFZ fault structure is located beneath the Marmara Sea, inhibiting geological and geomorphological investigations.

Despite its high exposure, seismic concerns and research were not focused on the Istanbul region until the 1999 Kocaeli and Duzce earthquakes because while the NAFZ has been very active east of the Gulf of Izmit, no significant earthquake has been recorded within the Marmara Sea since 1874. The lack of events in the region suggests a potential seismic gap that threatens Istanbul and its vicinity with a high probability of a large earthquake.

The RMS® Turkey Earthquake Model includes innovative techniques for modeling seismic source and recurrence uncertainty in the Marmara Sea region. These advancements are complemented by seismic attenuation relationships and vulnerability curves that have been developed and calibrated specific for the seismic environment and building practices in Turkey.

Model Highlights

	Alternate source models to account for uncertainty of fault structure in the Marmara Sea region
	Multiple recurrence models, including time-dependency and stress migration in the NAFZ
	Seismic attenuation functions calibrated against observations from 25 historic events in Turkey, including the 1999 Kocaeli and Duzce earthquakes
	High-resolution hazard data stored at Mahalle (district) resolution for Istanbul, and Ilce (sub-province) for the rest of Turkey
	Vulnerability functions calibrated specific to Turkey building characteristics, and additional vulnerability curves available for license with the RMS® Industrial Facilities Model
	Reviewed in consultation with local experts

Geographic Scope

All of Turkey

Exposure Data Resolution

Data input supported at the following levels of resolution: Latitude/Longitude, Mahalle (district) for Istanbul, City, Ilce (sub-province), Il (province), or CRESTA zone