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WOS: 000443414104104 …

In this study, the statistics properties of the aftershock sequence and Coulomb stress changes due to the mainshock of the = 6.3, 9 April 2013 Shonbe earthquake have been studied. The spatial distribution of aftershocks and focal mechanism event with ≥5.0 declared a NW–SE striking rupture with oblique thrust fault mechanism. The b-value is estimated as 0.77± 0.05 and the mainshock occurred in a highly stressed region and sequence comprised larger magnitude aftershocks due to the presence of large size asperities within the rupture zone. Also the high p-value (1.16 ± 0.05), implying fast decay rate of aftershocks, evidences high surface heat flux. A value of the spatial fractal dimension ( ) equal to 2.60 ± 0.02 indicates random spatial distribution and source in a two-dimensional plane that is being filled-up by fractures. Moreover, the evaluated coseismic Coulomb stress using the variable slip model for depth range 0–20 km reveals a ‘butterfly’ pattern and most of the aftershocks fall (95%) in the region of enhanced Coulomb stress.

The earthquake hazard parameters of a and b of Gutenberg-Richter relationships, return periods, expected maximum magnitudes in the next 100 years and probabilities for the earthquakes for certain magnitude values are computed using the earthquakes occurred between 1900 and 2014 years in and around Ağrı. The relation of LogN=4.73-0.68M is calculated for the studied area. The mapping of b values show that the regions in the east and southeast of Ağrı, east of Horasan and around Patnos where low b values are computed have high stress levels and capacity to occur large earthquakes in the future. It is found that earthquakes larger than 5.5 may be occurred in the regions where b values lower than 0.8 have been observed in the next 100 years. The return periods for magnitudes between 5.0 and 7.3 are estimated between 5 and 176 years in the studied area. The probabilities of an earthquake with M=6.0, 6.5 and 7.0 in the next 100 years are computed 99%, 86% and 59%, respectively. The largest earthquake occurred in the studied area is 7.3 and its probability to occur is 43% in the next 100 years. The faults around Ağrı are seismically active and have potential to an earthquake larger than 6.0. Since the sediment basin of Ağrı is very young and alluvial layer is tick, there is very high hazard on the buildings and human’s life in Ağrı.

The earthquake hazard parameters of a and b of Gutenberg-Richter relationships, return periods, expected maximum magnitudes in the next 100 years and probabilities for the earthquakes for certain magnitude values are computed using the earthquakes occurred between 1900 and 2014 years in and around Ağrı. The relation of LogN=4.73-0.68M is calculated for the studied area. The mapping of b values show that the regions in the east and southeast of Ağrı, east of Horasan and around Patnos where low b values are computed have high stress levels and capacity to generate large earthquakes in the future. It is found that earthquakes larger than 5.5 may be occurred in the regions where b values lower than 0.8 have been observed in the next 100 years. The return periods for magnitudes between 5.0 and 7.3 are estimated between 5 and 176 years in the studied area, respectively. The probabilities of an earthquake with M=6.0, 6.5 and 7.0 in the next 100 years are computed 99%, 86% and 59%, respectively. The largest earthquake occurred in the studied area is 7.3 and its occurrence probability is 43% in the next 100 years. The faults around Ağrı are seismically active and have potential for an earthquake larger than 6.0. Since the sediment basin of Ağrı is very young and alluvial layer is tick, there is very high hazard on the buildings and human’s life in Ağrı.

In this study, the statistics properties of the aftershock sequence and coulomb stress changes due to the mainshock of the = 6.3, 9 April 2013 Shonbeh earthquake have been studied. The spatial distribution of aftershocks and focal mechanism event with ≥5.0 declared a NW–SE striking rupture with oblique thrust fault mechanism. The bvalue is estimated as 0.77± 0.05 and the mainshock occurred in a highly stressed region and sequence comprised larger magnitude aftershocks due to the presence of large size asperities within the rupture zone. Also the high p-value (1.16 ± 0.05), implying fast decay rate of aftershocks, evidences high surface heat flux. A value of the spatial fractal dimension ) equal to 2.60 ± 0.02 indicates random spatial distribution and source in a two-dimensional plane that is being filled-up by fractures. Moreover, the evaluated coseismic Coulomb stress using the variable slip model for depth range 0–20 km reveals a ‘butterfly’ pattern and most of the aftershocks fall (95%) in the region of enhanced Coulomb stress.

Türkiye dünyanın sismik olarak en aktif bölgelerinden biri olan Alp-Himalaya kuşağında yer almaktadır. Bu aktivite nedeniyle Türkiye'de büyük depremler meydana gelmekte, çok sayıda can ve mal kaybı yaşanmaktadır. Türkiye için yapılan deprem tehlike haritaları genellikle deprem magnitüdleri kullanılarak yapılmasına rağmen son yıllarda şiddet değerleri kullanılarak hazırlanan haritalar dünya çapında yaygınlaşmaktadır. Bu çalışmada, Türkiye için ilk kez sismik tehlike analizinde konumsal yaklaşımı esas alan SASHA yöntemi kullanılarak makro sismik deprem tehlike haritası hazırlanmıştır. Bu haritanın hazırlanması için gerekli olan konum şiddeti (IS)-magnitüd (mw), episantr şiddeti (I0)-magnitüd (mw), konum şiddeti (IS)-PGA ilişkileri elde edilmiştir. Deprem tehlike haritası ise 50 yılda %2 (2475 yıl) ve %10 (475 yıl) aşılma olasılıkları için sismik tehlike analizinde konumsal yaklaşım yöntemi kullanılarak hesaplanmıştır. Kullanılan yöntem ile elde edilen şiddet değerlerinin III-XI arasında değiştiği gözlenmiştir. Geliştirilen şiddet (IS)-PGA ilişkisi kullanılarak, şiddet değerleri ivme değerlerine dönüştürüldüğünde ise ivme değerlerinin 0.1-1.0 g arasında değiştiği ve en yüksek değerlerin Kuzey Anadolu Fayı boyunca gözlendiği tespit edilmiştir. Klasik deprem tehlike haritalarında genellikle bir fay üzerinde aynı ivme değeri elde edilirken, bu çalışmada kullanılan konumsal yaklaşımda fay üzerinde sismik aktiviteye göre farklı değerler elde edilmektedir. Aletsel dönem verisine bağlı kalmaksızın, her döneme ait şiddet verisinin de sismik tehlike hesabında kullanılabilmesi Türkiye için önemli bir yeniliktir. Sonuç olarak deprem kataloglarının yalnızca aletsel büyüklüğe göre değil makro sismik şiddete göre de tutulması gelecekte yapılacak sismik tehlike haritalarının doğruluk payını arttıracaktır. Turkey is located in the Alpine-Himalayan belt one of the most seismically active regions in the world. This activity is due in large earthquakes occur in Turkey, many are experienced loss of life and property. Although earthquake hazard maps for Turkey usually perform using earthquake magnitude, the maps are prepared using intensity values are spread in recent years worldwide. In this study, macro seismic earthquake hazard map was prepared for Turkey using for the first time seismic hazard analysis based on the site approach SASHA method. Site intensity (IS)-magnitude (mw), epicentral intensity (I0)-magnitude (mW), site intensity (IS)-PGA correlations were obtained for the preparation of this map. The earthquake hazard maps were calculated using the site approach method for seismic hazard analysis for probabilities of exceeding 2% (2475 years) and 10% (475 years) in 50 years. It has been observed that the intensity values obtained by the method used vary between III-XI. When the intensity values were converted into acceleration values using the developed site intensity (IS)-PGA relationship, the PGA values were changed between 0.1-1.0 g and the highest values were observed along the North Anatolian Fault. While the same acceleration values on a fault are obtained on a classical earthquake hazard maps, different values are obtained according to the seismic activity on the fault using the site approach used in this study. Without depending on the instrumental data, intensity data of whole time period can be used the calculation of seismic hazard is an important innovation for Turkey. As a result, keeping seismic catalogs not only earthquake magnitude but also in macro seismic intensity will increase the accuracy of seismic hazard maps to be made in the future. 168