• Journal of the Korean earth science society
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• v.33 no.6
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• pp.534-543
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• 2012

The relationship between tectonic uplift and geophysical analysis of gravity anomalies and the in-situ stress fields in the Otway Ranges, SE Australia is addressed in this study to understand the nature and possible mechanism for the neotectonic movements. The uplift axis of the ranges is coincident with the regional Bouguer gravity highs whereas thick Tertiary sedimentary successions are highly correlated with the gravity lows along the basin rift geometry. This result suggests that the gravity highs are separated by the thick Tertiary sedimentary successions. Regional structural trends associated with faults and foldings of the deformed surfaces are consistent with the prevailing NW-SE $S_{Hmax}$ trend in this part of the continent. The anomalously positive correlation between topography and Bouguer gravity fields suggests possibly a lithospheric flexural deformation mode at a long wavelength (order of $10^2$ kms) in the region. It also suggests that the reactivation of pre-existing lithospheric structures driven by plate boundary forces plays a key role in this mode.

• Journal of the Korean association of regional geographers
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• v.18 no.4
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• pp.351-363
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• 2012

Although the Korean peninsula has been considered as a largely aseismic region compared with the surrounding high seismic areas such as North China and Japan, there are more than thirty Quaternary faults reported so far, which are mostly centered in the southeastern peninsula. Structural studies of active faults exposed in Yangnam-myeon of Gyeongju, SE Korea are largely interpreted to post date the late Quaternary, suggesting that the NE-trending reverse faults may result from the active stress regime in the peninsula. The prevailing present-day E-W $S_{Hmax}$ orientations in the peninsula are consistent with the nature of plate forcing stemming from the convergence between the Indo-Australian and Eurasian plates. It is clear that the Quaternary faults have been reactivated, although resolving more elaborate time intervals responsible for a future rupture remains a significant challenge. This study contributes to better assess many of potential seismic hazards in the study area, in particular, in terms of seismic stability for foundation of nuclear power plant.

• Journal of the Korean Geographical Society
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• v.47 no.3
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• pp.328-346
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• 2012

This study provides quantitative constraints on Neogene uplift in the Korean peninsula using onshore paleo-shoreline records and seismic data. The eastern margin of Northeast Asia including Korea sits in the back-arc system behind the Western Pacific Subduction Zone, a complex trench triple junction of the Philippine Sea, Pacific, and Eurasian (Amurian) plates. An analysis of seismic data in the subduction zone shows that the pattern of uplift in the peninsula mirrors the extent of deep seismicity in subducting Pacific plate beneath. Combined with previous tomographic studies it is proposed that uplift is partly driven by asthenospheric upwelling caused by a sinking slab during the Neogene. In addition, the SHmax orientations of E-W and N-S trends in the peninsula are consistent with the prevailing in-situ stress fields in the eastern Eurasian continent generated by various plate boundary forces. The uplift in Korea during the Late Neogene is attributed, in part, to lithospheric failure relating to faulting movements, thus providing a link between dynamic effects of mantle upwelling at sinking slab edge and lithospheric responses driven by plate boundary forces.