Spectral ratio 법을 이용한 탄성파 감쇠 특성 연구 = A Study on Characteristics of Seismic Attenuation by Using Spectral Ratio Method

다국어 초록 (Multilingual Abstract)

To enhance seismic images, seismic attenuation needs to be considered. There are various kinds ofmethods to analyze seismic attenuation. In this study, the quality factor, Q, which has an inverse relationshipwith seismic attenuation, was analyzed by the spectral ratio method. The method was first verified via physicalmodeling and numerical modeling. In other words, Q values of acrylic extracted in the physical modeling wasverified through the numerical modeling. For the analysis, we assumed normal-incidence seismic reflection survey,and investigated seismic attenuation of seismic reflections occurring at the interfaces. The spectral ratio methodwas applied to real field data acquired near Geo-je Island, and reliable Q factors were inferred from the attenuationof seismic reflections.

국문 초록 (Abstract)

현재 탄성파 자료의 정확한 영상화를 위한 자료 분석의 기법 중, 탄성파 감쇠의 영향에 대한 다양한연구들이 수행되고 있다. 본 연구에서는 실내시험분석방법으로 제안된 spectral ratio 법(Toksoz, 1979)를 이용하여 탄성파 감쇠와 반비례 관계를 가지는 quality factor(Q인자)를 분석하였다. 축소모형실험, 수치모형실험을 통해 Q값을 도출하고, 같은 방식을 현장자료에 적용하여 Q값을 추정하였다. 축소모형실험에서 아크릴의 Q값을도출하여 Q값 산출의 정확성을 검증하였으며, 수치모형실험을 통해 반사법, 수직입사 탐사법을 이용한 자료취득시 지층 경계에서 발생하는 탄성파 감쇠영향을 분석하여 Q값을 도출하였다. 최종적으로 거제도 인근 해역에서취득한 탄성파 반사법 현장자료에 적용하여 각 층의 반사면에 따른 감쇠정도에 대한 Q값을 추정하였다.

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