GRAVİTE BELİRTİSİ AYRIMI TEKNİKLERİ ÜZERİNE KARŞILAŞTIRMALI BİR ÇALIŞMA

Öz

Potansiyel alan yöntemlerinin doğasından dolayı elde edilen belirtiler sığ ve derin kökenli yapılardan kaynaklanan kısa ve uzun dalga boylu etkileri içerirler. Bu nedenle, gravite veya manyetik yöntemlerle gerçekleştirilen jeofiziksel aramada en önemli veri işlem adımlarından biri de belirti ayrımı işlemidir. Bu amaçla gözlemlenen veriyi rezidüel ve rejyonal belirti adı verilen iki bileşenine ayırmada bazı matematiksel teknikler kullanılmaktadır. Bu çalışmada, sonlu elemanlar yöntemi, tercihli filtreleme ve en uygun yukarı uzanım yüksekliği gibi üç hesaplama yönteminin etkinliği iyi bilinen ve günümüzde de en yaygın belirti ayrımı tekniği olarak kullanılan polinoma yaklaştırma yöntemiyle karşılaştırılmıştır. Uygulamada Jilin (Çin) manyetit alanı üzerinde alınmış gerçek gravite belirtisi kullanılmıştır. Elde edilen bulgular eleman şekil fonksiyonları kullanımıyla sonlu elemanlar yöntemi uygulamasının diğerlerine göre daha belirgin reziduel gravite belirtisi ürettiğini göstermiştir.

Anahtar Kelimeler

• Gravite Belirtisi Ayrımı
• Sonlu Elemanlar
• Filtreleme
• Yukarı Uzanım
• Polinoma Yaklaştırma

A COMPARISON STUDY ON THE GRAVITY ANOMALY SEPARATION TECHNIQUES

Öz

Due to the nature of the potential field methods obtained anomalies include both short and long wavelength effects caused by shallow and deeper causative sources. Thus, anomaly separation procedure is one of the most important data processing steps in geophysical prospection performed via gravity or magnetic method. To that end, some mathematical procedures are performed to separate the observed data into two components, namely residual and regional anomalies. In this study, the efficiencies of three computational processes named finite element method, preferential filtering and optimal upward continuation height have been compared with the well-known polynomial fitting method which is still the most commonly used anomaly separation technique in potential field methods. In the applications a real gravity anomaly observed over the Jilin (China) magnetite area has been considered. Findings obtained have shown that performing finite element method with the use of element shape functions provides clearer residual gravity anomaly patterns than those of the others.

Anahtar Kelimeler

• Gravity Anomaly Separation
• Finite Element
• Filtering
• Upward Continuation
• Polynomial Fitting

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