The Modern
Continental Slope Morphologies And Kinematics in The Ulleung Basin, Offshore Korea
Choi, Byeonggoo1,
Suyoung Choi2, Hun Jeong2, Ilsoo Kim2, Yongsu Lim2,
Donghyun Lim2, Seoungcheol
Lee2 (1) Korea National Oil Corporation (KNOC), Anyang,
South Korea (2) Korea National Oil Corporation (KNOC),
Modern continental slope morphologies in
the Ulleung Basin mainly resulted from
the tectonic movements and the developments of drainage systems during the
evolution of the backarc basin in the East Sea (Sea of Japan), offshore Korea. Evaluation of modern
slope processes and its depositions is difficult because of the limited
accessibilities arised from the deep water
environment. The recent 500 sq.km of 3-D and a few
thousands of 2-D seismic acquisition data have revealed two types of modern
continental slopes developed in the Basin. One is developed by the abrupt fault
block movements associated with the basin opening and the lack of drainage
system which was necessary for supplying sediments into the Basin caused the
high gradient angle (~ 4 degree) of modern continental slope morphology along
the eastern continental area of the Korean Peninsula. The other is shown in
the location around the low gradient angle (1.3-2.6 degree) of modern
continental slope, as it were, sharp and almost vertical slump scars with more
than 100m height are well developed across the water depth contours. From this
point of view, submarine sliding and slumping events were probably triggered by
the reactivation of the NW-SE trending trust faults generated by the collision
between the Eurasian and Pacific Plates during the Miocene. The faults might
have provided the well developed drainage systems which resulted in the low
gradient angle of slope at the present time. In conclusion, the evaluation of
geological histories is useful to understand the causes of modern continental
slope morphologies in the Ulleung Basin.