• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1997년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Fall 1997
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• pp.15-20
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• 1997

Source parameters of the December 13, 1996 Yeongweol earthquake are estimated using the grid test technique. Thirty polarities of P waves recorded at KMA, KIGAM, KSRS and JAPAN stations are used for the event. The obtained fault plane solution shows predominantly strike-slip motion with small amount of thrust component. The orientation of the fault is 180$\pm$10$^{\circ}$in strike, 50$\pm$5$^{\circ}$in dip and 150$\pm$5$^{\circ}$in rake, or 292$\pm$3$^{\circ}$in strike, 65$\pm$5$^{\circ}$in dip and 30$\pm$10$^{\circ}$ in rake. These solutions are very similar to those of earthquakes occurred at Sagju, Pohang and offshore Gunsan. The compressional axis of stress field is trending from ENE to WSW, which is consistent with the previously defined typical regional tectonic stress orientation in and around Korean Peninsula.. From the result of this study and other source mechanisms around the Korean Peninsula, we are of opinion that tectonic stress around the Korean Peninsula may be more attributed to the collision of Indian plate with the Eurasian plate than subduction of Pacific and Philippine plates.

• 한국지구물리탐사학회:학술대회논문집
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• 한국지구물리탐사학회 2007년도 특별 심포지엄 논문집
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• pp.73-83
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• 2007

We interpreted marine seismic profiles in conjunction with swath bathymetric and magnetic data to investigate rifting to breakup processes at the eastern Korean margin that led to the separation of the southwestern Japan Arc. Analysis of rift fault patterns suggests that rifting at the Korean margin was primarily controlled by normal faulting resulting from extension rather than strike-slip deformation. Two extension directions of E-W and NW-SE for rifting are recognized. We interpret that the E-W direction represents initial rifting at the inner margin and the NW-SE direction probably represents the extension in response to tensional tectonics associated with the subduction of the Pacific Plate in the NW direction. No significant volcanism was involved in rifting. In contrast, the inception of sea floor spreading documents a pronounced volcanic phase which appears to reflect asthenospheric upwelling as well as rift-induced convection particularly in the narrow southern margin. We suggest that structural and igneous evolution of the Korean margin, although it is in a back-arc setting, can be explained by the processes occurring at the passive continental margin with magmatism influenced by asthenospheric upwelling.

• 암석학회지
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• 제26권1호
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• pp.63-72
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• 2017

한반도 남서부 목포시에서 서쪽으로 약 90 km 지점에 위치한 흑산도의 소규모 화강암질 관입체로부터 분리한 저어콘에 대한 SHRIMP U-Pb 연대측정 결과 $113.9{\pm}1.2$(n=16) Ma의 정치연령을 얻었다. 백악기 앱티안-알비안 경계시기에는 한반도 거의 전역에서 화성활동이 나타났을 뿐만 아니라 중국 동부와 일본에서도 동일한 시기의 화성활동이 나타난 것으로 보고되었다. 평평한 각도로 일어난 섭입작용에 이은 엽렬에 의해 이처럼 일시적이지만 동아시아의 매우 넓은 지역에서 동시적인 화성활동을 만들어내었을 가능성이 있다.

• 자원환경지질
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• 제25권4호
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• pp.435-446
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• 1992

REE, major and trace elements analyses of the Jurassic Daebo granite and Cretaceous Bulguksa granite were carried out to interpet their petrogenesis and relationships between petrogenesis and tectonics. Analytical results are summarized as follows. (1) $SiO_2$ content of the Bulguksa granite (aver. 74.6%) are significantly higher than those of the Daebo granite (aver. 68.1%). Major elements of $TiO_2$, $Al_2O_3$, $P_2O_5$, CaO, MgO, Total FeO, and trace elements of Co, V and Sr are negatively correlated with $SiO_2$. Incompatible elements such as Ba, Sr, Y, Zr and HREE are contained differently in the Bulguksa granites distributed in between Okchon folded belt and Kyongsang sedimentary basin. (2) Trace element abundances show a good discrimination between two goups of granitic rocks. Ba, Sr and V are enriched in Daebo granites, while Zn and Cr are depleted in them. (3) Jurassic granites have quite different Eu anomalies and REE patterns from those of Cretaceous granites: Large negative Eu anomaly in the former and mild or absent Eu anomaly in the latter. The large Eu negative of Cretaceous granitic rocks are interpreted as a differentiated product of fractional crystallization of granitic magma from the upper mantle. Meanwhile, the Daebo plutonic rocks was resulted from the partial melting of subcrustal material or crustal contamination during ascending granitic magma from the mantle. Senario of igneous activities of Mesozoic age in South Korea was proposed based on Kula-Pacific ridge subduction model.

• 자원환경지질
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• 제47권6호
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• pp.601-610
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• 2014

제주도 동편의 부속섬인 우도는 일윤회 분출에 의해 형성된 단성화산체로서 해저에서 초기 서쩨이언형(Surtseyan-type)의 폭발성 화산분화에서 시작되고 마지막 용암분출로 섬 전체의 형태가 완성되었다. 섬의 대부분을 차지하는 소머리현무암은 서브알칼리계열로서 미량원소 및 희토류원소의 지화학적 특성은 섭입대에서 생성되는 쏠레이아이트일 가능성보다는 지각판내부에서 생성된 쏠레이아이트임을 지시하며, 이는 마이오세 말기 이후의 한반도의 화산활동은 태평양판과 필리핀해판인 해양판의 섭입 영향을 받지 않는 지구조적 환경으로 변했음을 시사한다.

• 지질공학
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• 제31권3호
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• pp.239-255
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• 2021

Kinematic analyses of magmatic intrusions and faults can provide useful information on stress conditions and chronological relationships between dike emplacement and brittle deformation events. We studied structures in rocks exposed on a coastal platform in Geoje Island off the southern Korean Peninsula because of its well-developed dikes and faults. The geology of the study area includes the Cretaceous Seongpo-ri Formation, which is composed mostly of shale, sandstone, and hornfels intruded by magmatic dikes. Most of the dikes are developed along pre-existing structural features (faults and fractures), indicating that their emplacements were structurally controlled. Because dikes commonly open along the direction of the minimum principal stress, the direction of this stress can be obtained from dike geometry and orientation through the matching of piercing points on either side of a dike. In addition, the deformed dikes can give information regarding later deformation. On the basis of the kinematic analyses, we identified five deformation events in the study area, which are kinematically related to changes of the regional maximum principal stress. Results indicate that the structures in the study area have been controlled predominantly by episodes of reactivation of the NNE-trending Yangsan strike-slip fault, located to the northeast of the study area, under different stress regimes. In a wider tectonic context, the brittle deformation of the rocks of Geoje Island was probably induced by interactions among the Philippine Sea, Pacific, and Eurasian plates, including changes in subduction parameters with respect to the latter two plates over time.

• Earthquakes and Structures
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• 제7권2호
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• pp.141-157
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• 2014

The Conditional Mean Spectrum represents a powerful link between the seismic hazard information and the selection of strong ground motion records at a particular site. The scope of the paper is to apply for the city of Bucharest for the first time the method to obtain the Conditional Mean Spectrum (CMS) presented by Baker (2011) and to select, on the basis of the CMS, a suite of strong ground motions for performing elastic and inelastic dynamic analyses of buildings and structures with fundamental periods of vibration in the vicinity of 1.0 s. The major seismic hazard for Bucharest and for most of Southern and Eastern Romania is dominated by the Vrancea subcrustal seismic source. The ground motion prediction equation developed for subduction-type earthquakes and soil conditions by Youngs et al. (1997) is used for the computation of the Uniform Hazard Spectrum (UHS) and the CMS. The disaggregation of seismic hazard is then performed in order to determine the mean causal values of magnitude and source-to-site distance for a particular spectral ordinate (for a spectral period T = 1.0 s in this study). The spectral period of 1.0 s is considered to be representative for the new stock of residential and office reinforced concrete (RC) buildings in Bucharest. The differences between the Uniform Hazard Spectrum (UHS) and the Conditional Mean Spectrum (CMS) are discussed taking into account the scarcity of ground motions recorded in the region of Bucharest and the frequency content characteristics of the recorded data. Moreover, a record selection based on the criteria proposed by Baker and Cornell (2006) and Baker (2011) is performed using a dataset consisting of strong ground motions recorded during seven Vrancea seismic events.

• 지구물리와물리탐사
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• 제13권3호
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• pp.295-300
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• 2010

최근 동해상의 일본 서해안을 포함한 태평양 연안의 지진대에서 큰 규모의 해저지진에 의한 지진해일이 자주 발생하고 있다. 지진해일은 수심이 깊은 대양에서 파고가 대략 수 m인데 반해 파장은 수십에서 수백 km에 달하는 장파로서, 선단파는 수심에 비례하여 매우 빠르게 이동할 수 있다. 따라서 지진해일은 인접국가 뿐만 아니라 발생지역으로부터 매우 먼 지역까지 전파하여 해안에 심각한 범람으로 인한 인명 및 재산피해를 일으킨다. 이러한 지진해일의 피해를 효율적으로 저감하는 방법은 해안지역을 따라 지진해일 재해정보도를 제작하고, 지역주민들에게 이를 배포하여 사전에 위험성을 알리고 지진해일 발생시 피해를 최소화할 수 있도록 대비하는 일이다. 지진해일 재해정보도는 과거의 지진해일 피해조사 결과와 계획된 시나리오를 바탕으로 만들어져야 하며, 실제 지진해일이 급습할 경우 주민들의 대피계획을 만드는 데 유용하게 사용된다.

• 대한원격탐사학회지
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• 제33권1호
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• pp.37-46
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• 2017

Sinabung volcano in Indonesia was formed due to the subduction between the Eurasian and Indo-Australian plates along the Pacific Ring of Fire. After being dormant for about 400 years, Sinabung volcano erupted on the 29th of August, 2010 and most recently on the 1st of November, 2016. We measured the deformation of Sinabung volcano using Advanced Land Observing Satellite/Phased Array type L-band Synthetic Aperture Radar(ALOS/PALSAR) interferometric synthetic aperture radar(InSAR) images acquired from February 2007 to January 2011. Based on multi-temporal InSAR processing, we mapped the ground surface deformation before, during, and after the 2010 eruption with time-series InSAR technique. During the 3 years before the 2010 eruption, the volcano inflated at an average rate of ~1.7 cm/yr with a markedly higher rate of 6.6 cm/yr during the 6 months prior to the 2010 eruption. The inflation was constrained to the top of the volcano. From the 2010 eruption to January 2011,the volcano subsided by approximately 3 cm (~6 cm/yr). We interpreted that the inflation was due to magma accumulation in a shallow reservoir beneath Sinabung. The deflation was attributed to magma withdrawal from the shallow reservoir during the eruption as well as thermo-elastic compaction of erupted material. This result demonstrates once again the utility of InSAR for volcano monitoring.

• 암석학회지
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• 제18권4호
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• pp.349-370
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• 2009

영남육괴의 남서부에 위치한 구례군 둥주리봉 화산암복합체는 백악기의 안산암과 유문암으로 구성된다. 화산암류의 $SiO_2$ 함량은, 52.0~78.5 wt.%의 넓은 조성범위를 나타내며, 칼크-알칼리 계열의 분화경향을 나타낸다. 주원소, 미량원소와 희토류원소의 패턴 및 조구조 판별도에 의하면, 연구지역의 화산암류가 지판이 침강 섭입하는 지판경계부에서 생성된 마그마로부터 유래된 대륙연변호 칼크-알칼리암 계열 화산암임을 지시한다. 화산암내 반정광물의 비평형 특징 즉, 휘석 결정 주변의 반응연의 존재, 사장석 결정의 역누대구조와 중심부의 융식구조, 석영 반정의 가장자리의 융식된 구조 등 마그마가 진화하는 동안 경험한 마그마혼합에서 나타나는 증거들이 비교적 잘 관찰된다.