Türkiye Ve Civarindaki Farkli Kaynak Bölgeler İçin Deprem Hazard Parametrelerinin Bölgesel Değişimleri Regional Variations of Earthquake Hazard Parameters for Different Source Regions in Turkey and Vicinity (original) (raw)
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An evaluation of seismic hazard parameters in southern Turkey
Journal of Seismology, 1999
To investigate the characteristics of earthquake hazard parameters as a means of identifying different zones of seismicity, we have compiled a catalogue of about 1850 moderate to large-sized earthquakes with magnitudes m≥4.0 or greater in southern Turkey for the time period from 1900 to 1990. Several methods have been applied to the earthquake catalogue to assess seismic hazard. The study area is divided into 77 overlapping cells of 2° size. Theoretical calculations were made for the prediction of maximum magnitude, intensity, b-values, strain energy release and corresponding m3 and peak ground acceleration levels for a given period of time. The resultant seismic hazard for each parameter is depicted as a contour map to indicate lateral variations in areas of seismic source. A combination and evaluation of various hazard parameters resulted in more reasonable estimates of hazard. It is found that the most hazardous seismic zones are the Rhodes and Burdur zones where the level of peak ground acceleration reaches up to 280 cm s-2 for an average return period of 100 years.
An Evaluation of Earthquake Hazard Parameters in and Around Ağrı, Eastern Anatolia, Turkey
Eastern Anatolian Journal of Science, 2015
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.
Natural Hazards, 2005
Turkey has been divided into eight different seismic regions taking into consideration the tectonic environments and epicenters of the earthquakes to examine relationships of the modal values (a/b), the expected maximum magnitudes (M max ) and the maximum intensities (I max ). For this purpose, the earthquakes for the time period 1900-1992 from the Global Hypocenter Data Base CD-ROM prepared by USGS, and for the time period 1993-2001 from the PDE data and IRIS data are used. Concerning the relationships developed between different magnitude scales and between surface wave magnitudes (M S ) and intensity for different source regions in Turkey, we have constructed a uniform catalog of M S . We have estimated the values of M max and I max using the Gumbel III asymptotic distribution. Highest a-values are observed in the Aegean region and the lowest b-values are estimated for the North Anatolian Fault. Maximum values of a/b, M max and I max are related to the eastern and western part of the North Anatolian Fault and the Aegean Arc. The lowest values of all parameters are observed near the Mid Anatolian Fault system. Linear relationships have been calculated between a/b, M max and I max using orthogonal regression. If one of the three parameters is computed, two other parameters can be calculated empirically using these linear relationships. Hazard maps of M max and I max values are produced using these relationships for a grid of equally spaced points at 1°. It is observed that the maps produced empirically may be used as a measure of seismic hazard in Turkey.
Earthquake hazard analysis for East Anatolian Fault Zone, Turkey
Natural Hazards, 2015
The aim of this study was to investigate the earthquake hazard of the East Anatolian Fault Zone by determining the a and b parameters in a Gutenberg-Richter magnitude-frequency relationship. For this purpose, the East Anatolian Fault Zone is divided into five different source zones based on their tectonic and seismotectonic regimes. We calculated the b value, which is the slope of the frequency-magnitude Gutenberg-Richter relationship, from the maximum likelihood method (ML). Also, we estimated the mean return periods, the most probable maximum magnitude in the time period of t years and the probability for an earthquake occurrence for an earthquake magnitude CM during a time span of t years. We then produced a and b value maps using the ML. We obtained the lowest b value in Region 1 covered Karlıova triple junction. This conclusion is strongly supported from the probability value, which shows the largest value (90 %) for an earthquake with magnitude greater than or equal to 6.0. The mean return period for such a magnitude is the lowest in this region (43 years). The most probable magnitude in the next 100 years was calculated, and we determined the highest value around Karlıova triple junction. According to these parameters, Region 1 covered the Karlıova triple junction and is the most dangerous area around the East Anatolian Fault Zone.
Turkey has been divided into eight different seismic regions taking into consideration the tectonic environments and epicenters of the earthquakes to examine relationships of the modal values (a/b), the expected maximum magnitudes (M max ) and the maximum intensities (I max ). For this purpose, the earthquakes for the time period 1900-1992 from the Global Hypocenter Data Base CD-ROM prepared by USGS, and for the time period 1993-2001 from the PDE data and IRIS data are used. Concerning the relationships developed between different magnitude scales and between surface wave magnitudes (M S ) and intensity for different source regions in Turkey, we have constructed a uniform catalog of M S . We have estimated the values of M max and I max using the Gumbel III asymptotic distribution. Highest a-values are observed in the Aegean region and the lowest b-values are estimated for the North Anatolian Fault. Maximum values of a/b, M max and I max are related to the eastern and western part of the North Anatolian Fault and the Aegean Arc. The lowest values of all parameters are observed near the Mid Anatolian Fault system. Linear relationships have been calculated between a/b, M max and I max using orthogonal regression. If one of the three parameters is computed, two other parameters can be calculated empirically using these linear relationships. Hazard maps of M max and I max values are produced using these relationships for a grid of equally spaced points at 1°. It is observed that the maps produced empirically may be used as a measure of seismic hazard in Turkey.
Pure and Applied Geophysics, 2012
We applied the maximum likelihood method produced by KIJKO and SELLEVOLL (Bull Seismol Soc Am 79:645-654, 1989; Bull Seismol Soc Am 82:120-134, 1992) to study the spatial distributions of seismicity and earthquake hazard parameters for the different regions in western Anatolia (WA). Since the historical earthquake data are very important for examining regional earthquake hazard parameters, a procedure that allows the use of either historical or instrumental data, or even a combination of the two has been applied in this study. By using this method, we estimated the earthquake hazard parameters, which include the maximum regional magnitudê M max ; the activity rate of seismic events and the well-knownb value, which is the slope of the frequency-magnitude Gutenberg-Richter relationship. The whole examined area is divided into 15 different seismic regions based on their tectonic and seismotectonic regimes. The probabilities, return periods of earthquakes with a magnitude M C m and the relative earthquake hazard level (defined as the index K) are also evaluated for each seismic region. Each of the computed earthquake hazard parameters is mapped on the different seismic regions to represent regional variation of these parameters. Furthermore, the investigated regions are classified into different seismic hazard level groups considering the K index. According to these maps and the classification of seismic hazard, the most seismically active regions in WA are 1, 8, 10 and 12 related to the Aliaga Fault and the Büyük Menderes Graben, Aegean Arc and Aegean Islands.
ASSESSMENT OF EARTHQUAKE HAZARD IN TURKEY AND NEIGHBORING REGIONS
Erdik, M., Y. Alpay Biro, T. Onur, K. Şeşetyan, G. Birgören, "Assessment of earthquake hazard in Turkey and neighboring regions" Annali Di Geofizica, Special Issue: Global Seismic Hazard Assessment Program (GSHAP) 1992-1999, 1999
The aim of this study is to conduct a probabilistic seismic hazard analysis for Turkey and neighboring regions, using the most recently developed attenuation relationships. The seismicity database is compiled from numerous sources, and the tectonic setting of the region has been studied in detail. Utilizing these two major categories of information together with the selected attenuation relationships, the seismic source zones are determined, and PGA contour maps are produced for specific return periods. The study is intended to serve as a reference for more advanced approaches and to stimulate discussion and suggestions on the data base, assumptions and the inputs, and to pave the path for the probabilistic assessment of the seismic hazard in the site selection and the design of engineering structures.