지구 조석 중력계에 의한 지구의 자유진동에 관한 연구

• 발행기관: 대한자원환경지질학회
• 저자명: 조원희 한욱
• 간행물 정보: 『자원환경지질』32권 6호, 653~660쪽, 전체 8쪽
• 주제분류: 자연과학 > 지질학
• 파일형태: PDF
• 발행일자: 1999.12.30

영문 초록

Any mechanical system has a natural oscillation which can be excited, and the earth is no exception. The earth can oscillate in an indefinite number of normal modes of oscillation, rather like a giant bell. The various free modes are generally sparated into two categoridal modes and toroidal modes. Clearly the toroidal modes will produce no perturvation of the gravity field and no vertical acceleration on the surface of the earth. Hence only spheroidal modes can be detected with a gravimeter. EarthTide gravimeter was installed at AIMST in order to observe free modes of the earth. Eight major earthquakes including chinese earthquake (magnitude 7.3) with free oscillations of the earth are observed during one year (1998. 8. 1∼1999.7.31). And then the earth tides components were eilminated from earthquake records using a numerical Butterworth highpass filter. Spectral analysis of gravity readings repersent that 48 observations of shheroidal modes. The relationships between instrumental observations and theoretical predictions based on the Gutenberg earth model agree well those resulting from free oscillation in Korea.

키워드

자유진동 지진학 지구 조석 중력계 스펙트럼 분석