Seismic and Structural Analyses of the Eastern Anatolian Region (Turkey) Using Different Probabilities of Exceedance (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.
Seismic hazard studies for Gaziantep city in South Anatolia of Turkey
Natural Hazards, 2007
Seismic hazard studies were conducted for Gaziantep city in the South Anatolia of Turkey. For this purpose, a new attenuation relationship was developed using the data of Zaré and Bard and accelerations were predicted employing this new equation. Deterministic approach, total probability theorem and GIS methodology were all together utilized for the seismic assessments. Seismic hazard maps with 0.258 grid intervals considering the site conditions were produced by the GIS technique. The results indicated that the acceleration values by the GIS hazard modelings were matched with the ones from the deterministic approach, however, they were underestimated comparing with the total probability theorem. In addition, the GIS based seismic hazard maps showed that the current seismic map of Turkey fairly yields conservative acceleration values for the Gaziantep region. Therefore, the constructed GIS hazard models are offered as a base map for a further modification of the current seismic hazard map.
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.
Seismic risk assessment of buildings in Izmir, Turkey
Natural Hazards, 2010
Izmir, the third largest city and a major economic center in Turkey, has more than three million residents and half million buildings. In this study, the seismic risk in reinforced concrete buildings that dominate the building inventory in Izmir is investigated through multiple approaches. Five typical reinforced concrete buildings were designed, modeled and assessed for seismic vulnerability. The sample structures represent typical existing reinforced concrete hospital, school, public, and residential buildings in Izmir. The seismic assessments of the considered structures indicate that they are vulnerable to damage during expected future earthquakes.
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The effects on structures of the earthquake with the magnitude of 7.8 on the Richter scale (moment magnitude scale) that took place in Pazarcık, Kahramanmaraş, Türkiye at 04:17 a.m. local time (01:17 UTC) on 6 February 2023, are investigated by processing suitable seismic records using the open-source software OpenSeismoMatlab. The earthquake had a maximum Mercalli intensity of XI (Extreme) and it was followed by a Mw 7.5 earthquake nine hours later, centered 95 km to the north–northeast from the first. Peak and cumulative seismic measures as well as elastic response spectra, constant ductility (or isoductile) response spectra, and incremental dynamic analysis curves were calculated for two representative earthquake records of the main event. Furthermore, the acceleration response spectra of a large set of records were compared to the acceleration design spectrum of the Turkish seismic code. Based on the study, it is concluded that the structures were overloaded far beyond their nor...
Analysis of building damage caused by earthquakes in Eastern Turkey
Numerous ground motions of various intensities have been registered in Eastern Turkey since 23 October 2011. Two of them resulted in severe loss of life and great material damage in the towns of Van and Erciş. More than 600,000 people were affected by damage caused by earthquakes in that period. Van is one of the most recent and fastest developing regions of Turkey, which is why thorough investigations must be made to check seismic properties of buildings erected in this region. Types of seismic damage inflicted on buildings, and causes of damage to various buildings built in Van and Erciş, are analysed in the paper.
Turkish Journal of Earth Sciences, 2021
We have investigated the time-dependent seismicity model of the earthquake occurrence on a regional basis through the North Anatolian Fault Zone (NAFZ). To that end, the studied region has been subdivided into 7 seismogenic zones considering the seismotectonic criteria, and then regional time and magnitude predictable (RTIMAP) model has been performed. Intervened times and magnitudes of main shocks produced in each zone have predictive properties defined by the RTIMAP. The probabilities of the next main shocks in 5 decades and the magnitudes of the next events have been estimated using the formation time and magnitude of the past events in the zones. In the second step of the study, we have considered 17 settlements located on the NAFZ to perform point-based site-specific seismic hazard analyses and to determine the design spectra and earthquake parameters using updated Turkish Earthquake Hazard Map. Eigen value and static adaptive pushover analyses have been applied for the sample reinforced concrete building using the design spectra obtained from each settlement. This sample building has been modelled with the same structural characteristics (i.e. material strength, column and beams, applied loads, etc.) for all of the settlements. We have determined that the earthquake building parameters differ from each other which indicates the significance of site-specific seismicity characteristics on the building performance.
Probabilistic seismic hazard analysis of Kahramanmaras Province, Turkey
Arabian Journal of Geosciences, 2018
Kahramanmaras and its surroundings are under the influence of East Anatolian and Dead Sea fault zones which have significance in the tectonics of Turkey. The long-term energy accumulation in these zones creates a very high risk level in terms of seismic hazard. In this study, the seismic hazard of Kahramanmaras Province and its vicinity was tried to be determined by using the probabilistic seismic hazard method approach. The earthquake catalog used in the study comprises 424 earthquakes equal or greater than M w = 4.0, covering a time period between 1 January 1900 and 1 January 2015. The earthquake data have been compiled from the catalogs of the International Seismological Center (ISC), Republic of Turkey Prime Ministry Disaster and Emergency Management Precidency (RTPMDEMP), Bogazici University Kandilli Observatory and Earthquake Research Institute. Seismic sources that could affect the study area have been identified according to the Earthquake Model of the Middle East (EMME). Seismic hazard parameters and peak horizontal acceleration values were obtained by using the selected attenuation relationships, and the results were given with iso-acceleration maps corresponding to a recurrence period of 475 years. The calculated peak horizontal acceleration values are generally varying between 0.21 and 0.41 in the study area. The result of this study shows that the southeastern parts of the study area have a greater seismic hazard compared with other parts.
Probabilistic earthquake hazard assessment for Ankara and its environs
TURKISH JOURNAL OF EARTH SCIENCES, 2014
The capital and the second largest city of Turkey, Ankara, is generally considered to be safe in terms of seismic activities and earthquake hazard. However, recent studies and earthquakes experienced in the region showed that Ankara is not indeed seismically safe. As the number of studies on Ankara's seismic hazard increases, the number of scientists who claim that the earthquake hazard in Ankara is higher than expected also increases. However, to date no detailed analysis has been undertaken as to the earthquake hazard facing Ankara. This study has compiled data from the earthquake catalogues available in Turkey and employed the latest knowledge available to produce an Ankara-specific earthquake catalogue. Probabilistic seismic hazard analysis of the unified data was then used to produced peak ground acceleration (PGA) values for 5%, 10%, 20%, and 40% probability of exceedance over a 50-year return period. The PGA values at main rock sites were determined using the most appropriate attenuation relationship. These show an exceedance probability of 10% over a 50-year return period to range from 0.20 g to 0.25 g for the Ankara provincial districts of Ayaş, Çankaya, Etimesgut, Sincan, and Yenimahalle; from 0.25 g to 0.30 g for Altındağ, Gölbaşı, Keçiören, and Mamak; and from 0.30 g to 0.35 g for Akyurt, Çubuk, Elmadağ, and Kazan.