Van Bölgesinde Yakın Saha Deprem Hareketlerinde Spektral Sönüm Parametresi, κ (kappa)

Öz

Anderson ve Hough (1984) tarafından ilk kez kullanılmaya başlanan spektral sönüm parametresi, κ (kappa), birçok uygulamada gittikçe artarak kullanılmaktadır ve bir istasyonda kaydedilmiş kuvvetli yer hareketinin spektral alanda yüksek frekanstaki eğimini ifade eder. Geçtiğimiz son yıllarda, kappa tahmini ve deprem tehlike analizi sonuçlarına etkisi üzerine birçok yaklaşım geliştirilmiştir. Kappa’nın zemin koşullarına bağlı olarak, yüksek frekans aralığındaki yer hareketinde deprem tehlike değerlerinde 3 hatta zemine bağlı olarak 6 kat artış gözlemlenmiştir. Bu parametrenin önemi sebebiyle Van Bölgesi için κ tespit edilmeye çalışılmıştır. Bu çalışmada, κ tahminleri için Afet ve Acil Durum Yönetimi Başkanlığı Kuvvetli Yer Hareketi gözlem ağına ait (AFAD) Van bölgesindeki istasyonlarından alınan ivme-ölçer deprem kayıtları kullanılmıştır.

Anahtar Kelimeler

• κ (kappa),stokastik simülasyon yer hareketi,GMPE’lerin (yer hareketi tahmin denklemleri) kaynak-hedef düzeltmeleri

The Spectral Decay Parameter κ (kappa) for the Near Site Events in Van Region

Öz

The spectral decay parameter κ (kappa) is increasingly used in many applications since it is first introduced by Anderson and Hough (1984) and basically measures the decay of high-frequency ground motion amplitudes for each ground motion acceleration time history record at one location. During the past years, multiple approaches were developed for its estimation and effect on seismic hazard calculations, where it was observed that κ can have an impact in terms of 3 to 6 times increased seismic hazard values for high-frequency ground motions depending on the site conditions. In this study, the strong ground motion recordings from the Disaster and Emergency Management Authority (AFAD) stations in Van region are taken into account for κ evaluations.

Anahtar Kelimeler

• κ (kappa),stochastic simulation of strong ground motion,host-to-target adjustments of GMPEs

Kaynakça

1. Abrahamson N., Silva W., 2008. Summary of the Abrahamson and Silva NGA Ground-Motion Relations. Earthquake Spectra (24), 67-97.
2. AFAD, 2018. Türkiye Ulusal Kuvvetli Yer Hareketi Veri Tabanı (TR-KYH), Ankara. Erişim adresi: http://kyhdata.deprem.gov.tr/2K/kyhdata_v4.php
3. Askan A., Sisman F.N., Pekcan O., 2014. A regional near-surface high frequency spectral attenuation (kappa) model for northwestern Turkey. Soil Dynamics and Earthquake Engineering (65), 113–125.
4. Anderson J., Hough S., 1984. A model for the shape of the Fourier amplitude spectrum of acceleration at high frequencies. Bulletin of Seismological Society of America (74), 1969-1993.
5. Andrews D.J., 1986. Objective determination of source parameters and similarity of earthquakes of different size. Earthquake source mechanics, American Geophysical Monograph (37), 259-267.
6. Biro Y., Renault P., 2012. Importance and impact of host-to-target conversions for ground motion equations in PSHA, Proceedings 15th World Conference of Earthquake Engineering (15WCEE), 24-28 September 2012, Lisbon-Portugal, 1855.
7. EPRI, 1993. Method and guidelines for estimating earthquake ground motion in eastern North America. Guidelines for Determining Design Basis Ground Motions, EPRI TR-102293, (Vol 1), Electric Power Research Institute, Palo Alto, CA, USA.
8. Kotha S.R., Bindi D., Cotton F., 2017. From ergodic to region-and site-specific probabilistic seismic hazard assessment: Method development and application at European and Middle Eastern sites. Earthquake Spectra, 33(4), 1433–1453.

9. Kurtulmus O., Akyol N., 2015. Separation of source, site and near-surface attenuation effects in western Turkey. Natural Hazards (77), 1515-1532.
10. Ktenidou O.J., Abrahamson N.A., Darragh R.B., Silva W.A., 2016. A methodology for the estimation of kappa (κ) from large datasets: Example application to rock sites in NGA-East database and implications on design motions. Pacific Earthquake Engineering Research Center (PEER), Report No: 2016/01, April 2016, CA, USA.
11. Ktenidou O.J., Silva W.A., Darragh R.B., Abrahamson N.A., Kishida T., 2017. Squeezing Kappa (κ) Out of the Transportable Array: A Strategy for Using Bandlimited Data in Regions of Sparse Seismicity. Bulletin of Seismological Society of America 107(1), 256-275.
12. Laurendeau A., Cotton F., Ktenidou O.J., Bonilla L.F., Hollender F., 2013. Rock and stiff-soil site amplification: Dependency on Vs30 and kappa (κ0). Bulletin of Seismological Society of America 103(6), 3131-3148.
13. Renault P., Abrahamson N.A., Coppersmith K.J., Koller M., Roth P., Hölker A., 2013. PEGASOS refinement project probabilistic seismic hazard analysis for Swiss Nuclear Power Plant Sites, Summary Report, Volumes 1-5, Swissnuclear, Switzerland.
14. SIGMA-2 Kappa Project, France. Erişim adresi: http://www.sigma-2.net
15. Tanircan G. and Dikmen S.U., 2018. Variation of high frequency spectral attenuation (Kappa) in vertical arrays. Soil Dynamics and Earthquake Engineering (113): 406-414.