Assessment of the statistical earthquake hazard parameters for NW Turkey
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Assessment of the statistical earthquake hazard parameters for NW Turkey Banu Akol • Tolga Bekler
Received: 18 June 2012 / Accepted: 21 March 2013 / Published online: 1 April 2013 Ó Springer Science+Business Media Dordrecht 2013
Abstract We performed a probabilistic analysis of earthquake hazard input parameters, NW Turkey covers Gelibolu and Biga Peninsulas, and its vicinity based on four seismic sub-zones. The number of earthquakes with magnitude M C 3.0 occurred in this region for the period between 1912 and 2007 is around 5130. Four seismic source sub-zones were defined with respect to seismotectonic framework, seismicity and fault geometry. The hazard perceptibility characterization was examined for each seismic source zone and for the whole region. The probabilities of earthquake recurrences were obtained by using Poisson statistical distribution models. In order to determine the source zones where strong and destructive earthquakes may occur, distribution maps for a, b and a/b values were calculated. The hazard scaling parameters (generally known as a and b values) in the computed magnitude–frequency relations vary in the intervals 4.28–6.58 and 0.59–1.13, respectively, with a RMS error percentage below 10 %. The lowest b value is computed for sub-zone three indicating the predominance of large earthquakes mostly at Gelibolu (Gallipoli) and north of Biga Peninsula (southern Marmara region), and the highest b value is computed for sub-zone two Edremit Bay (SW Marmara region). According to the analysis of each seismic sub-zone, the greatest risk of earthquake occurrence is determined for the triangle of Gelibolu–Tekirdag˘ western part of Marmara Sea. Earthquake occurrence of the largest magnitude with 7.3 within a 100-year period was determined to be 46 % according to the Poisson distribution, and the estimated recurrence period of years for this region is 50 ± 12. The seismic hazard is pronounced high in the region extending in a NW–SE direction, north of Edremit Bay, west of Saros Bay and Yenice Go¨nen (southern Marmara region) in the south. High b values are generally calculated at depths of 5–20 km that can be expressed as low seismic energy release and evaluated as the seismogenic zone. Keywords
Northwest Anatolia Seismic hazard Poisson distribution
B. Akol T. Bekler (&) Department of Geophysics Engineering, Faculty of Engineering, C¸anakkale Onsekiz Mart University, 17100 C¸anakkale, Turkey e-mail: [email protected]; [email protected]
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Nat Hazards (2013) 68:837–853
1 Introduction Even today, it is still uncertain where, when and at what magnitude an earthquake will occur. In seismically active regions, the evaluation of the probability of earthquake occurrence and their recurrence periods is very important for selection of settlement areas. The seismic hazard is defined as the potential of an earthquake to cause loss of life and property in a certain region within a certain period of time. The seismic hazard estimation, on the other hand, involves the evaluation of the seismicit
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