Attenuation of high-frequency P and S waves in the crust of chungcheong province, central south korea : 南韓 中部 忠淸地方 地殼의 P波 및 S波 減衰

국문 초록 (Abstract)

지진파가 전달되면서 진폭이 감소되는 정도를 나타내는 감쇠상수 Q^(-1)은 지구내부 물질의 물리적 성질을 나타내는 중요한 척도이다. 최근 새로운 행정수도의 이전이 예정된 남한 중부 충청지방에 대한 관심이 고조되고 있다. 우리는 이 지역에서 1996년 9월 이후 한국교원대학교 지진관측망을 설치하여 운영 중이며, 이 관측망 중 4개 관측소에서 기록된 72개의 지진자료를 바탕으로 확장coda규격화법(The extended coda normalization method)을 이용하여 Q_(P)^(-1)과 Q_(S)^(-1)을 동시에 측정하였다. 그리고 부족한 자료를 보충하기 위해서 한국지질자원연구원 관측망 중 한국교원대학교 관측망과 지리적으로 인접한 2개의 관측소에서 기록된 66개의 지진자료도 함께 분석하였다.
측정된 Q_(P)^(-1)은 (3.6±4.2)×10^(-3)에서 (6.3±0.1)×10^(-4)으로, Q_(S)^(-1)은 (2.2±4.4)×10^(-3)에서 (6.5±0.1)×10^(-4)으로 주파수가 1.5Hz에서 24Hz로 늘어남에 따라 줄어드는 주파수 의존적 특성을 보인다. 이들 값을 주파수의 지수형태로 나타내면 Q_(P)^(-1)이 0.003f^(-0.54), Q_(S)^(-1)이 0.003f^(-0.42)이다. 이 값들은 지진학적으로 안정한 지역의 값과 유사하며 남한 남동부 지역값에 비해서는 다소 약한 주파수 의존을 나타낸다. 이는 고주파수에서 높은 Q^(-1)값 때문이다. 남한 남동부와 남한 중부 지역 간의 Q^(-1)의 차이를 평가하기 위해서는 보다 많은 관측이 요구된다.

다국어 초록 (Multilingual Abstract)

Recently Chungcheong Provinces in the central part of South Korea has received increasing attention because of the newly planned administrative capital construction. In this area, a seismic network of Korea National University of Education has been installed since September 1996, and analyzed Q_(P)^(-1) and Q_(S)^(-1) by the extended coda normalization method based on 72 events recorded by four stations of the network. To compensate for insufficient data, data was combined from 66 events observed at two of the stations of the network of Korea Institute of Geosciences and Mineral Resources. Estimated Q_(P)^(-1) and Q_(S)^(-1) showed frequency dependence that decreases from (3.6 ± 4.2)×10^(-3) and (2.2 ± 4.4)×10^(-3) at 1.5 Hz to (6.3 ± 0.1)×10^(-4) and (6.5 ± 0.1)×10^(-4) at 24 Hz, respectively. Using a power law dependent on frequency, the best fit of Q_(P)^(-1) and Q_(S)^(-1) is 0.003f^(-0.54) and 0.003f^(-0.42), respectively. These values correspond to those of seismically stable regions, and are slightly less dependent on frequency than those of the southeastern part of Korea, due to high Q^(-1) values in high frequencies. Further observations are required to evaluate the difference of Q^(-1) in these two regions.

목차 (Table of Contents)

• CONTENTS = i
• LIST OF TABLES = ⅱ
• LIST OF FIGURES = ⅲ
• ABSTRACT = ⅴ
• Ⅰ. Introduction = 1
• Ⅱ. Method of Analysis and Data = 4
• 1. Definition of Q = 4
• 2. Extended coda-normalization method = 4
• 3. Data = 10
• Ⅲ. Measurements of QP^(-1) and QS^(-1) = 12
• Ⅳ. Discussion = 24
• Ⅴ. Conclusion = 27
• References = 28
• 論文要約 = 32
• Appendix = 34

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