Geophysics and Geophysical Exploration (지구물리와물리탐사)

Korean Society of Earth and Exploration Geophysicists (한국지구물리·물리탐사학회)
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Digital Gravity Anomaly Map of KIGAM

한국지질자원연구원 디지털 중력 이상도

  • Lim, Mutaek (Korea Institute of Geoscience and Mineral Resources) ;
  • Shin, Younghong (Korea Institute of Geoscience and Mineral Resources) ;
  • Park, Yeong-Sue (Korea Institute of Geoscience and Mineral Resources) ;
  • Rim, Hyoungrea (Department of Earth Science Education, Pusan National University) ;
  • Ko, In Se (Korea Institute of Geoscience and Mineral Resources) ;
  • Park, Changseok (Korea Institute of Geoscience and Mineral Resources)
  • Received : 2019.01.07
  • Accepted : 2019.02.25
  • Published : 2019.02.28
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Abstract

We present gravity anomaly maps based on KIGAM's gravity data measured from 2000 to 2018. Until 2016, we acquired gravity data on about 6,400 points for the purpose of regional mapping covering the whole country with data density of at least one point per $4km{\times}4km$ for reducing the time of the data acquisition. In addition, we have performed local gravity surveys for the purpose of mining development in and around the NMC Moland Mine at Jecheon in 2013 and in the Taebaeksan mineralized zone from 2015 to 2018 with data interval of several hundred meters to 2 km. Meanwhile, we carried out precise gravity explorations with data interval of about 250 m on and around epicenter areas of Gyeongju and Pohang earthquakes of relatively large magnitude which occurred in 2016 and in 2017, respectively. Thus we acquired in total about 9,600 points data as the result. We also used additional data acquired by Pusan National University for some local areas. Finally, gravity data more than 16,000 points except for the repetition and temporal control points were available to calculate free-air, Bouguer, and isostatic gravity anomalies. Therefore, the presented anomaly maps are most advanced in spatial distribution and the number of used data so far in Korea.

한국지질자원연구원에서 2000년부터 2018년까지 수행한 중력 탐사 자료를 처리하여 중력 이상도를 작성하였다. 2016년까지는 전국을 대상으로 하는 중력 이상도 작성에 필요한 자료를 빠르게 획득하기 위하여 약 $4km{\times}4km$ 당 1점의 측점 밀도로 약 6,400 점에서 측정을 하였다. 이와는 별개로 광산 개발과 관련하여, 관계 화성암 혹은 기반암의 분포를 규명하기 위하여, 2013년에는 제천 NMC 몰랜드 광산의 주변에서, 그리고 2015년에서 2018년까지는 태백산 광화대 일대에서 수백 미터에서 2 km 정도의 간격으로 탐사를 수행하였다. 한편 2016년과 2017년에는 경주와 포항에서 규모가 큰 지진이 발생하였는데, 이들 진앙지 일대에서는 측점 간격이 250 m 정도가 되도록 더욱 정밀하게 탐사를 하였다. 이들까지 포함한 전체 측점은 9,600여 점이다. 한편, 효율적인 탐사를 위하여 일부 지역에 대해서는 부산대학교의 자료를 사용하였다. 중복점과 임시 기준점을 제외하면 전체 측점은 약 16,000여 점이며, 이를 바탕으로 순높이 이상, 부게 이상, 지각 평형 이상을 계산하였다. 이 중력 이상도는 우리나라에서 가장 고르게 분포하면서 가장 많은 측점을 사용한 중력 이상도로서의 의미를 가진다.

Keywords

MRTSBC_2019_v22n1_37_f0001.png 이미지

Fig. 1. Gravity survey data distribution.

MRTSBC_2019_v22n1_37_f0002.png 이미지

Fig. 2. Network adjustment error (left) and points to be verified in the future (right).

MRTSBC_2019_v22n1_37_f0003.png 이미지

Fig. 3. Distribution of granitoids (left), Bouguer anomaly (middle) and isostatic anomaly (right): Tectonic zoning and classification of granitoids are referrred to Chough et al. (2000).

MRTSBC_2019_v22n1_37_f0004.png 이미지

Fig. 4. Comparison of isostatic anomaly maps and their data distribution: map by Shin et al. (2006) (left), isostatic anomaly map from the Bouguer anomaly map of KIGAM (2014) (middle), and map of this study (right).

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