• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.337-342
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• 2007

The representative Cretaceous-Tertiary paleomagnetic poles of the Korean Peninsula have been obtained from primary remanences of unremagnetized rocks: $59.6^{\circ}N$, $194.7^{\circ}E$ for $K_{1M}$; $67.6^{\circ}N$, $207.7^{\circ}E$ for $K_{1L}$; $71.1^{\circ}N$, $215.2^{\circ}E$ for $K_2$; and $84.9^{\circ}N$, $292.6^{\circ}E$ for the Miocene. Chemical remanences of remagnetized rocks also yield Early Tertiary paleomagnetic pole ($83.9^{\circ}N$, $88.3^{\circ}E$). These paleopoles provide the tentative APWP of the Korean Peninsula since the Cretaceous, and suggest some tectonic interpretations as follows. The Korean Peninsula was located at similar latitude to the present position, and rotated clockwise with respect to the adjacent blocks during the Cretaceous. The Korean Peninsula experienced latitudinal movement during the Early Tertiary, which was possibly associated with the continental collision between India and Asia. The Korean Peninsula and Southwest Japan might be independent terrains during the Cretaceous based on the temporal discrepancies of the southward movements and the clockwise rotations of the two blocks with respect to Eurasia.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.366-368
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• 2003

The Rann of Kachchh in Gujarat in the Western part of India is seismically the most active area outside Himalayan Belt. Several severe earthquakes of which the 1819 Rann of Kachchh and 2001 Bhuj Earthquakes are the severest recorded have rocked the region. This paper is an attempt to make a comparative study of the 1819,1844 and 2001 earthquakes. The study of 1819 and 1944 earthquakes is based on secondary accounts while 2001 Bhuj earthquake is based on remote Sensing. From a comparative study of the three earthquakes many interesting conclusions can be drawn. These earthquakes have been the result of accumulation of stress caused due to the collision of Indian Plate with the Eurasian Plate, which is continuously moving northwards. The earthquakes have been felt over large part of the Indian Sub-continent. These have resulted in creation of several faults that have activated periodically. Prominent of them are the Allah Bund Fault, Manfara Fault and Budharmora Fault. These are strike slip faults that get periodically activated. In future too these faults are going to be the most vulnerable to any seismic activity with the probability of high intensity earthquakes occurring along them in future too.

• The Journal of the Petrological Society of Korea
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• v.16 no.2 s.48
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• pp.82-99
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• 2007

The Paleogene dikes intruding into the late Cretaceous granodiorite are pervasively observed in the Irun-myeon, eastern Geoje Island. They are classified into three groups: NW-trending acidic dike swarm and WNW- (A-Group) and $NS{\sim}NNE-trending$ (B-Group) basic dike swarms. Based on their cross-cutting relationships, the earliest is the acidic dike group and fellowed by A- and B-Groups in succession. The acidic dikes seem to have intruded into tension gashes induced by the sinistral strike-slip faulting of the Yangsan fault system during the late $Cretaceous{\sim}early$ Paleogene. In terms of rock-type, orientation, age, and geochemistry, A-Group and B-Group are intimately correlated with the intermediate and basic dike swarms in the Gyeongju-Gampo area, respectively. These results significantly suggest that the corresponding dike swarms are genetically related. Based on the K-Ar and Ar-Ar age data, A- and B- Groups were intruded during $64{\sim}52\;Ma$ and $51{\sim}44\;Ma$, respectively. The result means that the direction of tensional stress in and around the SE Korean peninsula was changed abruptly from NNE-SSW to $EW{\sim}WNW-ESE$ at about 51 Ma. Considering the tectonic environments during the Paleogene, it is interpreted that A-Group was injected along the WNW-trending tensional fractures developed under an regional sinistral simple shear regime which was caused by the north-northwestward oblique subduction of the Pacific plate beneath the Eurasian plate. Meanwhile, the regional stress caused by the collision of India and Eurasia continents at about 55 Ma was likely propagated to the East Asia at about 51 Ma, and then the East Asia including the Korean peninsula was extruded eastwards as a trench-rollback and the dip of downgoing slab of the Pacific plate was abruptly steepened. As a result, the strong suction-force along the plate boundary produced a tensional stress field trending EW or WNW-ESE in and around the Korean peninsula, which resultantly induced B-Group to intrude passively into the study area.