Within the framework of the performance based earthquake engineering, the seismic hazardanalysis for the Van province in Turkey is performed in probabilistic manner. It is noteworthy that, in probabilistic seismic hazard assessment, as a first stage, data from geological studies and records from the instrumental period were compiled to make a seismic sourcecharacterization for the study region. Then, a seismic hazard model by using EZ-FRISKsoftware is implemented and the probabilistic seismic hazard curves were developed based onthe selected appropriate attenuation relationships, at rock sites, with a probability ofexceedance of 2%, 10% and 50% in 50-year periods. The results of probabilistic seismic hazard analyses revealed peak acceleration values for a typical rock site as 0.47g for 50%probability of exceedance in 50 years, 1.09g for 10% probability of exceedance in 50 yearsand 1.91 g for 2% probability of exceedance in 50 years. The obtained results are comparedwith N-S&amp;E-W component taken from Muradiye station after the earthquake which occurred on 23.10.2011 in Van, N-S &amp; E-W component taken from Van station after thee arthquake which occurred on 9.11.2011 in Van, and the spectral responses proposed forseismic evaluation and retrofit of building structure in Turkey Earthquake Code, Section 7.At the end of this study, it is apprehended that for the performance evaluation of the existing structures Code proposed earthquake response spectra are not sufficient and the currente stimations show that the potential seismic hazard in research area of the Turkey is not well estimatedin the code.

Hakan Ulutas

Mustafa Kutanis

Epoka University

International Students’ Conference of Civil Engineering, ISCCE 2012, 10-11 May 2012, Epoka University, Tirana, AlbaniaSeismic Hazard Analysis Of Van Province Of TurkeyHakanUlutaş1, Mustafa Kutanis21Department of Civil Engineering, Gümüşhane University, Gümüşhane, Turkey2Department of Civil Engineering,Sakarya University,Sakarya, TurkeyABSTRACTWithin the framework of the performance based earthquake engineering, the seismic hazardanalysis for the Van province in Turkey is performed in probabilistic manner. It is noteworthythat, in probabilistic seismic hazard assessment, as a first stage, data from geological studiesand records from the instrumental period were compiled to make a seismic sourcecharacterization for the study region. Then, a seismic hazard model by using EZ-FRISKsoftware is implemented and the probabilistic seismic hazard curves were developed based onthe selected appropriate attenuation relationships, at rock sites, with a probability ofexceedance of 2%, 10% and 50% in 50-year periods. The results of probabilistic seismichazard analyses revealed peak acceleration values for a typical rock site as 0.47g for 50%probability of exceedance in 50 years, 1.09g for 10% probability of exceedance in 50 yearsand 1.91 g for 2% probability of exceedance in 50 years. The obtained results are comparedwith N-S&E-W component taken from Muradiye station after the earthquake whichoccurred on 23.10.2011 in Van, N-S & E-W componenttaken from Van station after theearthquake which occurred on 9.11.2011 in Van, and the spectral responsesproposed forseismic evaluation and retrofit of building structure in Turkey Earthquake Code, Section 7.At the end of this study, it is apprehended that for the performance evaluation of the existingstructures Code proposed earthquake response spectra are not sufficient and the currentestimations show that the potential seismic hazard in research area of the Turkey is not well-estimated in the code..Blank line 10 pKeywords: Seismic Hazard, Performance Evaluation, Response Spectra, Van provinceBlank line 11 pank line 11 pt1. INTRODUCTIONBlank line 11 ptVan is a city at an altitude of 1750 metres in southeastern Turkey's Van Province, and islocated on the eastern shore of Lake Van. In 2010 the official population figure for Van wasnearly 500,000. The city land is surrounded by volcanic high mountains. Its history dates toB.C. 10. Century and its original name is Tuşba.The seismicity of Van has been investigated in the light of performance based –engineering inthis study. Performance-based earthquake engineering seeks to improve seismic risk decision-making through assessment and design methods that have a strong scientific basis and thatexpress options in terms that enable stakeholders to make informed decisions. Given theinherent uncertainty and variability in seismic response, it follows that a performance-basedmethodology should be formalized within a probabilistic basis. The framework has four mainanalysis steps: Hazard analysis, structural/nonstructural analysis, damage analysis, and lossInternational Students’ Conference of Civil Engineering, ISCCE 2012, 10-11 May 2012, Epoka University, Tirana, Albaniaanalysis. The first assessment step entails a hazard analysis, through which one evaluates oneor more ground motion Intensity Measures (IM). For standard earthquake intensity measures(such as peak ground acceleration or spectral acceleration) is obtained through conventionalprobabilistic seismic hazard analyses. Typically, IM is described as a mean annual probabilityof exceedance, which is specific to the location and design characteristics of thefacility(Moehle and Deierlein, 2004).In this study, a probabilistic seismic hazard analysis is applied for the assessment of potentiallosses as a part of an ongoing research entitled as Seismic Hazard and Risk Assessment ofVan.Blank line 11 ptnk line 11 ptBlank line 11 pt2. METHODOLOGYThe seismic hazard analysis approach is based on the model developed originally by Cornell(1968) who quantified it in terms of the probability of exceedance of the design level peakground acceleration (PGA).  The procedure for conducting a probabilistic seismic hazardanalysis includes seismic source characterization, size distribution and rate of occurrencedetermination for the source, ground motion estimation and, lastly, probability analysis.In the current study, since the neotectonic faults are not identified in the research area clearly,earthquake sources are characterized as area source zones. Area seismic sources are oftendefined where specific fault data are not known, but seismicity does exist. Area sourcesassume that the rate of occurrence is uniform throughout. Therefore, every location within thearea has equal probability that an event will occur.All seismic sources, that can generate strong ground shaking  in Van and surroundings, areclassified into 12 areal seismic zones: (Fig.1) (1) Bitlis Zagros Suture zone; (2) Başkale faultzone; (3) HasanTimur fault zone; (4) Malazgirt fault zone; (5) Erciş fault zone; (6) SuphanFault zone ; and (7) Van Like Southern Boundary fault (Utkucu, 2006) (8) Çaldıran fault zone(9) First fault zone (Ketin, 1977) (10)Second fault zone (Ketin, 1977) (11) Third fault zone(Ketin, 1977) (12) Fourth fault zone (Ketin, 1977).Figure 1. Earthquake areal zones (Bitlis Zagros Suture zone, Başkale fault zone, HasanTimur fault zone,Malazgirt fault zone, Erciş fault zone, Suphan Fault zone, Van Like Southern Boundary fault,  Çaldıran faultzone, First fault zone, Second fault zone, Third fault zone, Fourth fault zone) in Van and surroundingsBlank line11 ptOn any given fault within any given region, earthquakes occur at irregular intervals in time,International Students’ Conference of Civil Engineering, ISCCE 2012, 10-11 May 2012, Epoka University, Tirana, Albaniaand one of the basic activities in seismology has long been the search for meaningful patternsin the time sequences of earthquake occurrence (Dowrick, 2003). Among a number ofrecurrence laws have been proposed, in this study, Gutenberg and Richter law was used.Because, there is no available evidence to determine whether the Gutenberg –Richter or someother recurrence laws are correct.During any given interval in time, the general underlying pattern or distribution of size ofevents is that first described by Gutenberg and Richter, who derived an empirical relationshipbetween magnitude and frequency of the formlog N = a − b.M (1)where N is the number of shocks of magnitude at least M per unit time and unit area, and Aand b are seismic constants for any given region (Dowrick, 2003).In a seismic hazard modeling study of Van, a plot of M against log N was constructedbyutilizing the values indicated in Table 1 and the best-fit line of the form of Eqn. 1 wasdetermined by regression analysis (Fig. 2).Tablo 1.Recurrence numbers of earthquakes in terms of magnitude and the logarithmic values of theserecurrence numbersMs AverageMs Frequency Log N Mass Frequency Log N4,0 -- 4,5 4,25 65 1.81291 140 2,146124,5 -- 5,0 4,75 42 1.62324 75 1,875065,0 -- 5,5 5,25 18 1.25527 33 1,518515,5 -- 6,0 5,75 10 1.00000 15 1,176096,0 – 6,5 6,25 4 0.60205 5 0,698976,5 – 7,0 6,75 1 0,00000 1 0,00000Figure 2.Gütenberg-Richter magnitude–frequency relationship for earthquakes from Van and surrounding dataIn probabilistic seismic hazard analysis, beside magnitude–frequency relationship which iscalculated for Van province as logN = 5,8248 – 0,8344 M , a relationships between magnitudeand fault rupture parameters of length Lsub(km), width W (km), area A (km2) and displacementD (m) is also required. In a study of a worldwide database of 244 earthquakes, for strike-slipfault types Wells and Coppersmith (1994) obtained:Mw = 4.33 + 1.49 logLsub       s = 0.2 (2)0.00.20.40.60.81.01.21.41.61.82.02.22.44 4.5 5 5.5 6 6.5 7LogNMagnitud (Ms)International Students’ Conference of Civil Engineering, ISCCE 2012, 10-11 May 2012, Epoka University, Tirana, Albaniawheres is the residual standard deviationIn Eastern Anatolia region, previously recorded strong ground motion acceleration records arelimited. Therefore, in this current analysis, worldwide applicable three empirical attenuationrelationships are utilized to perform the seismic hazard analysis. Attenuation relationships forrock sites employed in this study are Abrahamson-Silva (1997), Ambraseys et al. (2005),Boore - Joyner - Fumal (1997) and Idriss (2008) Fig. 3.Figure 3.Abra-Silva (1997), Ambraseyes et al (2005),  Boore-Joyner-Fumal (1997)and Idriss (2008) attenuationrelationships for rock sites.3. SEISMIC HAZARD ANALYSIS RESULTSAfter the compilation of the seismic hazard analysis data, the procedure for conducting aprobabilistic seismic hazard analysis, by using EZ-FRISK (Risk Engineering, Inc, 1997;McGuire R., 2004) software, was employed to produce the PGA as a function of returnperiods (Figure 4), and uniform probability response spectra for selected return periods (Fig.5)The results of probabilistic seismic hazard analysis for Van are presented in terms of spectralresponses at 5% damping for the return periods of 72, 474.6 and 2474.9 years (Fig. 5). Theresults are compared with N-S&E-W component taken from Muradiye station after theearthquake which occurred on 23.10.2011 in Van, N-S & E-W component taken from Vanstation after the earthquake which occurred on 9.11.2011 in Van, and the spectralresponsesproposed for seismic evaluation and retrofit of building structure in TurkeyEarthquake Code, Section 7.The results of probabilistic seismic hazard analyses revealed peak acceleration values for atypical rock site as 0.47g for 50% probability of exceedance in 50 years, 1.09g for 10%probability of exceedance in 50 years and 1.91g for 2% probability of exceedance in 50 years.The obtained results are compared with N-S&E-W component taken from Muradiye stationafter the earthquake which occurred on 23.10.2011 in Van, N-S & E-W component takenfrom Van station after the earthquake which occurred on 9.11.2011 in Van, and the spectralInternational Students’ Conference of Civil Engineering, ISCCE 2012, 10-11 May 2012, Epoka University, Tirana, Albaniaresponsesproposed for seismic evaluation and retrofit of building structure in TurkeyEarthquake Code, Section 7.(Fig. 5).Figure 4. Peak ground acceleration (PGA) atVan with varying return periodsFig. 5a.Comparison of the spectral response ofpresent study andTurkey Earthquake Code at 5% damping for thereturn period of 72 years in Van-0.251E-150.250.50.750 0.5 1 1.5 2 2.5 3Spectral Acceleration (g)Spectral Period (s)PROBABILITY OF EXCEEDENCE50.0 % IN 50.0 YEARSPresentTEC 2007 Ground Type Z3International Students’ Conference of Civil Engineering, ISCCE 2012, 10-11 May 2012, Epoka University, Tirana, AlbaniaFig. 5b.Comparison of the spectral responses ofpresent study andTurkey Earthquake Code at 5% damping for thereturn period of 74,6 years in VanFig. 5c.Comparison ofthe spectral responses ofpresent study andTurkey Earthquake Code at 5% damping for thereturn period of 2474,9 years in VanFig. 5d.Comparison of 23.10.2011 Muradiye Station N-S & E-W components, TEC 2007 GroundTypeZ3,andpresentstudy00.250.50.7511.250 0.5 1 1.5 2 2.5 3Spectral Acceleration (g)Spectral Period(s)PROBABILITY OF EXCEEDENCE10.0 % IN 50.0 YEARSPresentTEC 2007 Ground Type Z300.511.520 0.5 1 1.5 2 2.5 3Spectral Acceleration (g)Spectral Period (s)PROBABILITY OF EXCEEDENCE2.0 % IN 50.0 YEARSPresentTEC 2007 Ground Type Z300.250.50.7511.250 0.5 1 1.5 2 2.5 3Spectral Acceleration(g)Spectral Period(s)23.10.2011 Muradiye Station N-S & E-W components,TEC 2007 Ground Type Z3, PresentPresentMuradiye E-WTEC 2007 Ground Type Z3Muradiye N-SInternational Students’ Conference of Civil Engineering, ISCCE 2012, 10-11 May 2012, Epoka University, Tirana, AlbaniaFig. 5e. Comparison of 9.11.2011 Muradiye Station N-S & E-W components, TEC 2007 GroundTypeZ3,andpresentstudy4. SUMMARY AND CONCLUSIONSBy utilizing available data and the use of improved methods, a probabilistic seismic hazard ofVan province in Turkey was determined. The study is conducted under the ongoing researchentitled as Seismic Hazard and Risk Assessment of Van city. As a first step of theperformance based earthquake engineering, it is well understood that the Code proposedspectra should be studied in more detail to represent earthquake demand in the performanceevaluation.The results of this work will form the basis for the replacement of the existingearthquake design spectra in evaluation of earthquake performances of the existing buildingsin Van province.In this study, since active faults are not identified clearly, regional areas were used as anearthquake source zones. Future work will increase the resolution of the seismotectonic modelby adding specific active faults.REFERENCESAbrahamson, N.A. and Silva.(1997)  W.J. Empirical Response Spectral Attenuation Relationsfor Shallow Crustal Earthquakes.Seismological Research Letters.Vol. 68, No. 1, pp. 94-127.Ambraseys, N.N., Douglas, J., Sarma, S.K., andSmıt, P. M. (2005) EquationsfortheEstimationof StrongGroundMotionsfromShallowCrustalEarthquakes Using Data from EuropeandtheMiddle East: HorizontalPeakGround Acceleration andSpectral Acceleration, Bulletin ofEarthquakeEngineering, 3:1–53, [DOI 10.1007/s10518-005-0183-0].Idrıss, I.M.(2008) An NGA Empirical ModelforEstimatingtheHorizontalSpectralValuesGeneratedByShallowCrustalEarthquake,EarthquakeEngineeringResearchInstitute, EarthquakeSpectra, Volume 24, No. 1, pages217-242,Armenian Soviet Encyclopedia, Vol. 2. Yerevan. Armenian Academy of Sciences, 1976, pp.254-256.Boore, D.M. Joyner, W.B. Joyner and T.E. Fumal. (1997) Equations for EstimatingHorizontal Response Spectra and Peak Acceleration from Western North AmericanEarthquakes: A Summary of Recent Work. Seismological Research Letters.Vol. 68, No. 1, pp128-153.Bozkurt, E. (2001). Neotectonics of Turkey-a synthesis.GeodinamicaActa (Paris) 14,3-30Ketin İ.(1977) A short explanation about the observations made in the region between Lake00.250.50.7511.250 0.5 1 1.5 2 2.5 3Spectral Acceleration (g)Spectral Period(s)9.11.2011 Van Station N-S & E-W components,TEC 2007 Ground Type Z3, PresentVan E-WTEC 2007 Ground Type Z3Van N-SPresentInternational Students’ Conference of Civil Engineering, ISCCE 2012, 10-11 May 2012, Epoka University, Tirana, AlbaniaVan and Iran borderline, Buttetin of theGeologicalBodety of Turkey, vol. 20, pp. 79-85.Dowrick, D. (2003)  Earthquake Risk Reduction, Wiley, England.Cornell, C.A. (1968) Engineering seismic hazard analysis, Bull. Seismol. Soc. Am.59 (5), pp.1583–1606.KOERI.http://www.koeri.boun.edu.tr/sismo/default.htmMcGuire R. (2004) Seismic Hazard and Risk Analysis, 2004, EERI, Oakland, CA.Moehle, J. and Deierlein, G.,G. (2004) A Framework Methodology For Performance-BasedEarthquake Engineering. 13th World Conference on Earthquake Engineering, Vancouver,B.C., Canada, August 1-6, 2004, Paper No. 679Risk Engineering, Inc. (1997)  EZ-FRISK  User’s Manual.Turkey Earthquake Code. (2007)Utkucu, M. (2006)  Implications for the water level change triggered moderate (M ≥ 4.0)earthquakes in Lake Van basin, Eastern Turkey. Journal of Seismology.10: 105–117324Wells, D.L. and Coppersmith, K.J. (1994) New Empirical Relationships amongMagnitude, Rupture Length, Rupture Width, Rupture Area, and Surface DisplacementBulletinof the Seismological Society of America, Vol. 84, No. 4, pp. 974-1002.

Seismic Hazard Analysis Of Van Province Of Turkey

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Seismic Hazard Analysis Of Van Province Of Turkey

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