Estimation of Seismic Hazard: Probabilistic and Statistical Methods

Öz

Considering the aleatory uncertainties related to earthquake occurrences with respect to time, space, magnitude and the additional epistemic uncertainties, probabilistic methods appear to be more appropriate. However, in implementing the probabilistic and statistical methods, engineers very seldom check the validity of the underlying assumptions with respect to the available data. This may lead to serious errors and most often those who apply these methods are unaware of the resulting errors. In this paper, the basic steps for the development of seismic hazard maps are stated together with the necessary background and supporting information for the implementation of these steps. Also attention is drawn to the possible errors committed in utilizing the statistical methods for the assessment of seismic hazard.

Anahtar Kelimeler

• Probabilistic Seismic Hazard Analysis
• Orthogonal Regression
• Renewal Model
• Magnitude-Recurrence Relationship

Sismik Tehlikenin Tahmini: Olasılık ve İstatistik Yöntemleri

Öz

Deprem oluşumlarının zaman, yer ve şiddet bakımından gösterdikleri rassallık ve çeşitli belirsizlikler nedeni ile sismik tehlikenin tahmininde olasılık ve istatistik yöntemlerine dayanan bir yaklaşım gereklidir. Ancak bu yöntemler, çoğunlukla, eldeki verilerin ve fiziksel olayların uygulanan stokastik modellere uyumları kontrol edilmeden kullanılmaktadır. Böyle bir yaklaşım hatalı sonuçlara yol açabilmekte, çoğu kez de uygulayıcılar bu durumun farkında olmamaktadır. Deterministik yaklaşımlara karşın, olasılık ve istatistik kuramları çerçevesinde geliştirilen bir yöntemin katkısı, yer hareketi değişkenleri için tek bir değer yerine bir değerler kümesi ile bu küme üzerinde tanımlanmış bir olasılık dağılımının belirlenmesi şeklinde olmaktadır. Bu bildiride sismik tehlike analizinin temelini oluşturan modeller özetlenerek, özellikle aktif faylara ağırlık verilerek geliştirilecek olan sismik tehlike haritalarının oluşturulmasında kullanılacak stokastik modeller üzerinde durulmuş ve yukarıda söz edilen muhtemel hatalı uygulamalara dikkat çekilmiştir.

Anahtar Kelimeler

• Olasılıksal Sismik Tehlike Analizi
• Ortogonal Regresyon
• Yinelenme Modeli
• Magnitüd-Tekerrür İlişkisi

Kaynakça

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