Northern Barbados accretionary prism: Structure, deformation, and fluid flow interpreted from 3D seismic and well-log data

Cukur, Deniz,Lee, Gwang H.,Um, Jeong G.,Kim, Dae C.,Kim, Jin H. Wiley (Blackwell Publishing) 2009 The island arc Vol.18 No.4

Evidence of extensive carbonate mounds and sublacustrine channels in shallow waters of Lake Van, eastern Turkey, based on high-resolution chirp subbottom profiler and multibeam echosounder data

Cukur, D.,Krastel, S.,Ç,ağ,atay, M. N.,Damcı, E.,Meydan, A. l.,Kim, S. P. Springer Science + Business Media 2015 Geo-marine letters Vol.35 No.5

Geophysical evidence and inferred triggering factors of submarine landslides on the western continental margin of the Ulleung Basin, East Sea

Cukur, D.,Kim, S. P.,Kong, G. S.,Bahk, J. J.,Horozal, S.,Um, I. K.,Lee, G. S.,Chang, T. S.,Ha, H. J.,Vö,lker, D. Springer Science + Business Media 2016 Geo-marine letters Vol.36 No.6

<P>Submarine landslides form very complex depositional and erosional features on the seafloor, and their dynamics and triggering processes are yet to be understood completely. Numerous studies are being undertaken both because of the scientific significance but also for their potential harm to seafloor infrastructure and coastal areas. This study investigates the styles and causes of landsliding along the western margin of the Ulleung Basin in the East Sea, based on multiple sparker, subbottom profiler, multibeam echosounder and sediment core datasets collected in 2015. The bathymetric analyses indicate that the southern slope of the Ulleung Basin has experienced at least seven submarine failures. These failures left clear arcuate-shaped scarps that initiated at water depths of similar to 600 m. The observed headwall scarps have heights that exceed 60 m and appear to be the result of retrogressive-type failures. Seismic reflection data clearly image the basal sliding surface that is characterized by a prominent high-amplitude reflector. Chaotic-totransparent seismic facies occur immediately downslope of the headwall scarps; these represent similar to 20 m thick landslide deposits. Gravity cores taken from areas adjacent to the scars suggest that these slides are older than ca. 97 ka. Interpretation of the present data shows that faults appear to cut recent sediments upslope of scarps, and that the slope may still be in an active phase of failure. Seismic data also image various overpressurized gases and/or gas fluids, as evidenced by the occurrence of pockmarks and seismic chimneys in upslope or adjacent areas of the scarps. Hence, earthquakes associated with tectonic activity and development of fluid overpressure may have acted as the main conditioning factor for destabilizing the slope sediments. Geotechnical stability analyses indicate that the sampled slope sediments are exceptionally stable under present-day conditions, even under seismic loading. This finding points to additional forces such as excess pore pressure caused by gas fluids at the times of slide emplacement.</P>

Morphology and genesis of giant seafloor depressions on the southeastern continental shelf of the Korean Peninsula

Cukur, Deniz,Kong, Gee-Soo,Chun, Jong-Hwa,Kang, Moo-Hee,Um, In-Kwon,Kwon, Taekhyun,Johnson, Samuel Y.,Kim, Kyong-O Elsevier 2019 Marine geology Vol.415 No.-

<P><B>Abstract</B></P> <P>We identify and describe five giant seafloor depressions from the southeastern continental shelf of the Korean Peninsula using multibeam bathymetry, sub-bottom profiler, and multi-channel seismic reflection data, supplemented by piston cores. Multibeam bathymetry data from the shelf show four crescent-shaped depressions (SD1 to SD4) and one near-circular depression (SD5) within a group of NW-SE trending depressions, the largest covering an area of about 7 km<SUP>2</SUP> on the seafloor. The depressions reach up to ~4.5 km in width and ~2 km in length and have asymmetric cross-sections. Some have depths as large as 40 m below the surrounding seafloor with walls as steep as 45°. The depressions are confined to water depths between 130 and 170 m and bounded on the north by a large submarine channel that was plausibly formed by fluvial or tidal processes during the Last Glacial Maximum (LGM) sea-level lowstand. Multi-channel seismic and sub-bottom profiler data reveal truncated depression walls and the presence of sediment drift deposits within the depressions, indicating that both erosion and deposition are active processes. Flaser and lenticular bedding in the cored drift deposits along with variable grain size (ranging between ~2.6 phi and ~4.3 phi) are diagnostic features of the bottom currents influenced by tidal forces. Depressions SD1 to SD4 lack evidence of fluid or gas escape. In contrast, many features of depression SD5 are characteristic of gas escapes and blowouts, including acoustic anomalies, a 20-m-high carbonate mound or carbonate-encrusted mound, and mud dikes and mud patches in cores. Based on the SD5 example, we think it is likely that the other crescent-shaped seafloor depressions formed originally as pockmarks by gas/fluid venting, and have since become inactive. The pockmarks represent zones of weakened sediment that were eroded, expanded, and merged by bottom currents to form larger seafloor depressions. Modern currents are strong enough to transport shelf sediments, and these currents were probably much stronger at lower sea levels when the Korea Strait was a more restricted passage between the East China Sea and East Sea.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Four crescent-shaped seafloor depressions (SD1 to SD4) from the SE shelf of Korea </LI> <LI> These depressions have 25 to 40 m of depths below the adjacent shelf </LI> <LI> Evidence of drift deposits inside the depressions and erosion at the depression walls </LI> <LI> SD1 to SD4 probably began as pockmarks and then were modified by submarine currents </LI> <LI> We also document a smaller circular depression (SD5) that we consider as pockmark </LI> </UL> </P>

Seismic stratigraphy and structural analysis of the western South Korea Plateau (WSKP), East Sea

Cukur, D.,Kim, S.P.,Horozal, S.,Ryu, B.J.,Kim, G.Y.,Kong, G.S. Pergamon Press 2015 Quaternary international Vol.384 No.-

The western South Korea Plateau (WSKP), situated on the southwestern part of East Sea, is characterized by rifted continental fragments that were formed in the early phase of back-arc opening. In this work, we analyze multi-channel seismic reflection profiles from the WSKP to document the structural and stratigraphic framework of the area. We also present fault-derived stretching (beta) factors related to the continental rifting along two regional seismic profiles. Our data reveal several graben and half graben subbasins, up to 1300 m thick, bound by N-S trending normal faults. We show that, on the basis of constructed isopach maps, tectonic activity was the main controlling factor on the sedimentation through much of the plateau history. The seismic data reveal that the sedimentation history of the WSKP is characterized by four main phases (Phase 1 to Phase 4; P1-P4) separated by regional unconformities. Rapid extension and subsidence took place at an early stage of P1 leading to the graben and half-graben openings. Volcanic activity was widespread at early times and ~700 m thick succession of lacustrine and fluvial sediments was deposited. Following P2 (early mid Miocene - latest Miocene), dramatic extension and subsidence changed the lacustrine environment into marine, enabling to the deposition of thick marine sediments (~750 m) over the subbasins. Extension ceased during P3 (latest Miocene - early Pliocene) and less pronounced subsidence continued. At this time, the sedimentation was uniform over the area and included the cyclic succession of hemipelagic deposits and turbidites which were probably expressed by climatic forcing. P3 was interrupted by regional compression, when normal fault movement was reversed and gentle anticlines formed as a result of inversion. The latter was accompanied by widespread uplift and erosion along the western margin of the plateau, and substantial erosion took place on the crests of the folds. The uplift also shifted the main depocenters of the plateau which were ultimately filled by thick mass-transport deposits during the following phase of P4 (early Pliocene - Holocene). Subsidence has been dominant in the area since the beginning of P4, which was locally interspersed by inversion along the reactivated normal faults. Total upper-crust (βf) and whole-crust extension (βc) estimates in the WSKP show similarities, suggesting that the observed rift structure in WSKP has resulted from uniform pure-shear stretching.

Seismic stratigraphy and structural characteristics of the northeastern continental margin of Korea in the East Sea (Sea of Japan)

Cukur, Deniz,Um, In-Kwon,Bahk, Jang-Jung,Chun, Jong-Hwa,Horozal, Senay,Kim, So-Ra,Kong, Gee-Soo,Kim, Kyong-O.,Kim, Seong-Pil Elsevier 2018 Marine and petroleum geology Vol.98 No.-

<P><B>Abstract</B></P> <P>The northeastern continental margin of Korea in the East Sea (Japan Sea) is a narrow sedimentary apron 20–30 km wide, 50–1300 m below sea level, with an average gradient of less than 2°. The present study focuses on seismic stratigraphy of the sedimentary section and the underlying basement structure of the margin based primarily on multi-channel seismic reflection profiles. Major accumulation of sediment is centred in a graben depocenter in the northern part of study area, where more than 2 km of sediments have been deposited. This graben widens towards north and is flanked by two major basement bounding faults. The sedimentary succession of the margin can be divided into six seismic stratigraphic units based on reflection character, onlapping, and erosional truncation. The lowermost seismic unit (SU1) is characterized by parallel-to subparallel-reflections with varying amplitudes and is interpreted to be representing shallow-to non-marine sediments that were deposited during the active extensional phase of margin development. The presence of erosional channels in the uppermost section of SU1 further suggests a lowstand period after the deposition of SU1. Unconformably overlying the SU1 is a few hundred metres of SU2 that is characterized by continuous, high-amplitude reflections. Continuous seismic reflections within SU2 are indicative of sea level rise immediately following the lowstand period. The overlying seismic unit sets include SU3, SU4, and SU5 with well-stratified seismic reflections. The consistent reflection pattern and high continuity of the reflections within these units are indicative of relatively stable depositional environments within the margin. Hemipelagic sediments and turbidites are probably the main components of these units. The youngest seismic unit SU6 comprises well-stratified seismic reflections in the upper slope and chaotic-to transparent-seismic reflections in the lower slope. The sedimentary units characterized by well-stratified seismic reflections are typical for hemipelagic slope sediments while chaotic seismic reflections are diagnostic features for mass-transport sediments (MTDs; i.e., slides/slumps, debris-flow deposits). The preferential occurrence of MTDs adjacent to the major faults suggests that they may be due to earthquakes associated with tectonic activity.</P> <P>Seismic reflection data from the margin reveal the coexistence of four structural styles including the basement-involved normal faults, reverse faults, reactivated normal faults, and anticline folds. The basement-bounding normal faults are associated with the initial extension of the continental margin while the others are postulated as resulting from contractional tectonism of the eastward movement of the Amur Plate that began in the early Pliocene. The prominent seafloor erosion over the folded/inverted blocks further suggests that inversion continues today.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A tectonostratigraphic framework for the northeastern margin of Korea is developed. </LI> <LI> Six seismic units have been defined in analysis of the seismic reflection profiles. </LI> <LI> Primary deposits consist chiefly of hemipelagites interbedded with turbidites. </LI> <LI> Basement structure and seismic stratigraphy suggest a rift origin for the margin. </LI> <LI> Regional compression in the Pliocene reactivated the earlier extensional faults. </LI> </UL> </P>

Seismic-Stratigraphic study of the northern East China Sea shelf basin : Basin structure and igneous activity

DENIZ CUKUR,GWANG HOON LEE,HYUN CHUL HAN,KANG MOO HEE,KYUNG O KIM 대한지질학회 2008 대한지질학회 학술대회 Vol.2008 No.

Submarine landslides along the western margin of the Ulleung Basin, East Sea

Deniz Cukur,Seong-Pil Kim,Gee-Soo Kong,Jang-Jun Bahk,Senay Horozal,In-Kwon Um,Gwang-Soo Lee,Tae-Soo Chang,Hun-Jun Ha,David Volker 대한지질학회 2016 대한지질학회 학술대회 Vol.2016 No.10

Barbados accretionary prism : Evidence of deformation, fluid flow and faulting from 3-D seismic and well-log data

Deniz Cukur,Gwang Hoon Lee,Dae Choul Kim 대한지질학회 2006 대한지질학회 학술대회 Vol.2006 No.

Role of Expression of Inflammatory Mediators in Primary and Recurrent Lumbar Disc Herniation

Dagistan, Yasar,Cukur, Selma,Dagistan, Emine,Gezici, Ali Riza The Korean Neurosurgical Society 2017 Journal of Korean neurosurgical society Vol.60 No.1

Objective: To assess role of some inflammatory mediators in patients with primary and recurrent lumbar disc herniation. Expression of IL-6, transforming growth factor (TGF)-1, insulin-like growth factor (IGF)-1, and Bcl-2-associated X protein (BAX) have been shown to be more intense in the primary group than the recurrent goup, but this mediators may be important aspects prognostic. Methods: 19 patients underwent primary and revision operations between June 1, 2009 and June 1, 2014, and they were included in this study. The 19 patients' intervertebral disc specimens obtained from the primary procedures and reoperations were evaluated. Expression of IL-6, TGF-1, IGF-1, and BAX were examined immunohistochemically in the 38 biopsy tissues obtained from the primary and recurrent herniated intervertebral discs during the operation. Results: For IL-6 expression in the intervertebral disc specimens, there was no difference between the groups. The immunohistochemical study showed that the intervertebral disc specimens in the primary group were stained intensely by TGF-1 compared with the recurrent group. Expression of IGF-1 in the primary group was found moderate. In contrast, in the recurrent group of patients was mild expression of IGF-1. The primary group intervertebral disc specimens were stained moderately by BAX compared with the recurrent group. Conclusion: The results of our prognostic evaluation of patients in the recurrent group who were operated due to disc herniation suggest that mediators may be important parameters.