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