• 지구물리
• /
• 제9권3호
• /
• pp.209-217
• /
• 2006

The major continental blocks in NE-Asia are the North China Block and the South China Blo, which have collided, starting from the Korean peninsula. The suture zone in NE China between two blocks is well defined from the QinIing-Dabie-Orogenic Belt to the Jiaodong (Sulu) Belt by the geological and geophysical interpretation. The discovery of high pressure metamorphic rocks in the Hongsung area of the Korean peninsula can be used to estimate the suture zone. This indicates that the suture zone in the Jiaodong Belt might be extended to Hongsung area. However, due to the lack of geological and geophysical data over the Yellow sea, the extension of the suture zone to the Korean peninsula across the Yellow Sea is obscure. To find out the tectonic relationship between NE China and the Korean peninsula it is necessary to complete U-ie homogeneous geophysical dataset of NE Asia, which can be provided by satellite observations. The CHAMP lithospheric magnetic field (MF3) and CHAMP-GRACE gravity field, combined with surface measured data, allow a much more accurate in-ference of tectonic structures than previously available. The CHAMP magnetic anomaly map reveals significant magnetic lows in the Yellow Sea near Nanjing and Hongsung, where are characterized by gravity highs on U-ie CHAMP-GRACE gravity anomaly map. To evaluate the depth and location of poten-tial field anomaly causative bodies, the Euler Deconvolution method is implemented. After comparing the two potential field solutions with the simplified geological map containing tectonic lines and the distribution of earthquakes epicenters, it is found that the derived structure boundaries of both are well coincident with the seismic activities as well as with the tectonic lineaments. The interpretation of the CHAMP satellite magnetic and GRACE satellite gravity datasets reveal two tectonic boundaries in U-ie Yellow Sea and the Korean peninsula, indicating U-ie norttiern and southern margins of the suture zone between the North China Block and the South China Block. The former is extended from the Jiaodong Belt in East China to the Imjingang Belt on the Korean peninsula, the later from Nanjing, East China, to Hongsung, the Korean peninsula. The tectonic movement in or near the suture zone might be responsible for the seismic activities in the western region of the Korean Peninsula and the development of the Yellow Sea sedimentary basin.

• 자원환경지질
• /
• 제54권1호
• /
• pp.117-126
• /
• 2021

위성고도에 획득한 지각 자기이상값들은 지상부근(near-surface)의 항공탐사나 해양탐사등에서 얻은 자기이상값들에서 얻기 어려운 장파장의 특징을 보이며 이들은 지각의 자기현상이 소멸되는 큐리 등온 깊이선(Curie isotherm)까지의 심부 지각물질의 자기특징 및 위성고도에서도 나타날 수 있는 강한 자기특징들을 반영한다. 따라서 심부 지하구조나 판구조론을 통한 과거 지구조의 재구성(reconstruction) 및 해석과 최근 지구온난화로 인한 대륙빙하의 해빙과 연관되어 남극 및 그린랜드의 지열분포 연구에 중요한 자료로 이용되고 있다. 이러한 위성 지각 자기이상값은 전지구를 경계조건으로 하는 구면조화함수의 계수모델로 표현되는 것이 일반적이나 많은 계수 계산과 함께 안정적으로 외부자기장을 분리하기 어려운 극지역 및 적도지역의 자료들도 포함되어 이들 자료가 모델 전체에 영향을 줄 수가 있다. 한편, 이와는 달리 관심지역의 자료들만을 가지고 지역에 맞는 몇 단계 자료처리 과정을 거쳐 얻은 지각 자기이상값들은 이러한 영향에서 벗어날 수 있다. 본 연구에서는 한반도를 중심으로 하는 동아시아 지역(20° ~ 55°N, 108° ~ 150°E) 의 CHAMP 위성에서 최저고도였던 시기의 자료를 획득하여 평균 280 km 에서의 지각 자기이상 지도를 제작하고 CHAMP 자료로 만든 전지구 지각 자기이상 모델(MF7)과 비교하여 지각 자기이상 특징들을 파악하고자 한다. 아울러 전세계 지상부근 지각자기이상 자료를 종합하여 제작한 EMAG2에서 장파장 성분을 추출하여 함께 비교하기로 한다.

• 대한원격탐사학회지
• /
• 제21권1호
• /
• pp.91-98
• /
• 2005

On board satellite magnetometer measures all possible magnetic components, such as the core and crustal components from the inner Earth, and magnetospheric, ionospheric and' its coupled components from the outer Earth. Due to its dipole and non-dipole features, separation of the respective component from the measurements is most difficult unless the comprehensive knowledge of each field characteristics and the consequent modeling methods are solidly constructed. Especially, regional long wavelength magnetic signals of the crust are strongly masked by the main field and dynamic external field and hence difficult to isolate in the satellite measurements. In particular, the un-modeled effects of the strong auroral external fields and the complicated behavior of the core field near the geomagnetic poles conspire to greatly reduce the crustal magnetic signal-to-noise ratio in the polar region relative to the rest of the Earth. We can, however, use spectral correlation theory to filter the static lithospheric and core field components from the dynamic external field effects that are closely related to the geomagnetic storms affecting ionospheric current disturbances. To help isolate regional lithospheric anomalies from core field components, the correlations between CHAMP magnetic anomalies and the pseudo-magnetic effects inferred from satellite gravity-derived crustal thickness variations can also be exploited, Isolation of long wavelengths resulted from the respective source is the key to understand and improve the models of the external magnetic components as well as of the lower crustal structures. We expect to model the external field variations that might also be affected by a sudden upheaval like tsunami by using our algorithm after isolating any internal field components.