지구물리와물리탐사 (Geophysics and Geophysical Exploration)

  • 제22권2호
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  • Pages.80-87
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  • 2019
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  • 1229-1064(pISSN)
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  • 2384-051X(eISSN)
한국지구물리·물리탐사학회 (Korean Society of Earth and Exploration Geophysicists)
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고정밀 중력탐사 자료의 광역-나머지 이상 분리

Regional-residual Separation of Microgravity Data

  • 임형래 (부산대학교 지구과학교육과) ;
  • 박계순 (한국지질자원연구원 DMR 융합연구단) ;
  • 김창렬 (한국지질자원연구원 광물자원연구본부)
  • Rim, Hyoungrea (Department of Earth Science Education, Pusan National University) ;
  • Park, Gyesoon (Convergence Research Center for Development of Mineral Resources, KIGAM) ;
  • Kim, Chang-Ryol (Mineral Resources Research Division, KIGAM)
  • 투고 : 2019.05.03
  • 심사 : 2019.05.24
  • 발행 : 2019.05.31
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초록

이 논문에서는 사전 정보가 없는 경우 고정밀 중력 탐사 자료를 광역-나머지 이상으로 분리할 때 중력 이상 자료의 특성을 바탕으로 다항식 접합법을 적용하는 방법을 제시하였다. 소규모 영역을 대상으로 하는 고정밀 중력 탐사는 1차 평면으로 광역 이상을 근사하는 것이 이상적인데 중력 이상의 패턴이 1차 평면으로 근사하기 어려운 경우, 먼저 완전 부게 이상을 Parasnis 밀도 추정 방법으로 분석한 후 중력 이상을 1차 평면으로 근사 가능하도록 분할하였다. 다항식 접합법으로 중력 이상을 광역-나머지 이상으로 분리할 때 중력 이상 자료가 지질 구조 및 중력 이상 분포 특성을 바탕으로 공간적으로 분할이 가능한 경우에는 전체 측정 자료를 한꺼번에 분리하지 않고 구획된 각각의 영역에서 광역-나머지 이상을 별도로 분리하는 것이 더 효과적임을 보였다.

In this paper, we propose a method to apply the polynomial fitting for regional-residual separation of microgravity data based on the characteristics of gravity anomaly without a prior information. Since the microgravity survey is usually carried out in small regions, it is common to approximate regional anomaly by the first-order polynomial plane. However, if the regional anomaly patterns are difficult to be approximated to a first-order plane, the complete gravity anomaly is divided into small zones enough to approximate first-order plane by means of Parasnis density estimation method. The regional-residual separation is then applied on the splitted zones individually. When the gravity anomalies can be splitted spatially, we showed that the residual anomalies can be more effectively extracted based on the regional geological structures by regional anomaly separation from each of the divided regions, rather than applying the entire data set at one time.

키워드

MRTSBC_2019_v22n2_80_f0001.png 이미지

Fig. 1. Gravity observation stations on the topography.

MRTSBC_2019_v22n2_80_f0002.png 이미지

Fig. 3. Complete Bouguer anomaly.

MRTSBC_2019_v22n2_80_f0003.png 이미지

Fig. 4. Regional and residual anomaly maps from all data by polynomial fitting method: regional anomaly by (a) the first and (b) second orders, and residual anomaly by (c) the first and (d) second orders.

MRTSBC_2019_v22n2_80_f0004.png 이미지

Fig. 5. Density estimation by Parasnis method using (a) all the data, (b) the data within the northern part, and (c) those within the southern part of the study area.

MRTSBC_2019_v22n2_80_f0005.png 이미지

Fig. 6. Regional and residual anomaly maps from splitting data as northern and southern areas by polynomial fitting method: regional anomalies by (a) the first and (b) second orders, and residual anomalies by (c) the first and (d) second orders.

MRTSBC_2019_v22n2_80_f0006.png 이미지

Fig. 7. Comparing ranges of residual anomalies according to polynomial orders and applied areas.

MRTSBC_2019_v22n2_80_f0007.png 이미지

Fig. 2. (a) Free-air anomaly and (b) simple Bouguer anomaly.

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