The distribution and characteristics of the igneous complexes in the northern East China Sea Shelf Basin and their implications for hydrocarbon potential   总被引：2，自引：0，他引：2  

Deniz Cukur  Senay Horozal  Dae C. Kim  Gwang H. Lee  Hyun C. Han  Moo H. Kang 《Marine Geophysical Researches》2010,31(4):299-313

This paper presents results of two-dimensional seismic mapping of the northern East China Sea Shelf Basin. Various igneous features such as sills, volcanic edifices and stocks were identified by the geophysical exploration. The sills are most common, and are observed at more than 90 locations. Most mapped sills in the study area are characterized by high-amplitude continuous reflections with distinct terminations. Saucer- and cup-shaped sills are observed locally. The stocks are discordant (nearly vertical) igneous bodies and they are characterized by seismic transparency, with upturned host rocks and uplifted overburden. The volcanic edifices and/or necks consist of irregular mounds and peaks and are characterized by strong positive top reflections with chaotic internal facies. The oldest igneous activity in the northern East China Sea Shelf Basin is Early Cretaceous (123.3 ± 3.7). This igneous activity coincides with those observed in eastern China which has been related mainly to the subduction of the Pacific Plate beneath Eurasia Plate. The Miocene igneous activity is well constrained based on seismic stratigraphic relationships within the folded stratigraphy, age dating, and the occurrence of igneous sills. The timing of this intrusion is coincident with the intensive igneous activity as previously suggested for the eastern China. Igneous rocks can produce hydrocarbon traps, reservoirs and they can act as a seal, and therefore are of great importance in petroleum study.  相似文献   

Identification and characterization of the encrusting materials in a coastal liquefied petroleum gas storage cavern     

Jin-Yong Lee  Hyoun Soo Lim 《Environmental Earth Sciences》2010,61(6):1165-1177

An examination was carried out of the encrusting materials on the seepage removal pumps in a bottom sump of an undersea liquefied petroleum gas (LPG) cavern. The studied cavern, constructed at 8 km off the western coast of Korea, facing the Yellow Sea, is at 130–150 m below the seabed. Since the first filling of the LPG into the cavern, it has suffered from the unexpected problem of a thick encrustation of unknown materials on the seepage removal pumps of the cavern. The XRD and XRF analyses revealed that the encrustation materials were mainly iron (hydro)oxides and carbonate mineral (aragonite). Based on the geological setting below the cavern site, it was inferred that iron oxides found in the Pleistocene sandy sediment and the Precambrian gneiss might be supplying ferrous iron to the cavern waters under an anaerobic condition, evidenced by low dissolved oxygen and negative redox potential in the cavern water. A significant change in the hydraulic condition near the pump intake and mixing the cavern water with oxic waters supplied through re-circulated seawater and terrestrial groundwater discharge, would precipitate the dissolved iron. Precipitation of the carbonate mineral is thought to have occurred due to over-saturation of calcium and bicarbonate, which may have resulted from the dissolution of cement grouting materials used during the undersea cavern construction and submarine groundwater discharge (SGD). This study reports the iron and carbonate precipitation in the man-made undersea cavern, which is affected by the surrounding hydrogeological condition and the SGD.  相似文献   

A Numerical Study of Sea-Fog Formation over Cold Sea Surface Using a One-Dimensional Turbulence Model Coupled with the Weather Research and Forecasting Model     

Chang Ki Kim  Seong Soo Yum 《Boundary-Layer Meteorology》2012,143(3):481-505

The formation mechanism of a cold sea-fog case observed over the Yellow Sea near the western coastal area of the Korean Peninsula is investigated using numerical simulation with a one-dimensional turbulence model coupled with a three-dimensional regional model. The simulation was carried out using both Eulerian and Lagrangian approaches; both approaches produced sea fog in a manner consistent with observation. For the selected cold sea-fog case, the model results suggested the following: as warm and moist air flows over a cold sea surface, the lower part of the air column is modified by the turbulent exchange of heat and moisture and the diurnal variation in radiation. The modified boundary-layer structure represents a typical stable thermally internal boundary layer. Within the stable thermally internal boundary layer, the air temperature is decreased by radiative cooling and turbulent heat exchange but the moisture loss due to the downward vapour flux in the lowest part of the air column is compensated by moisture advection and therefore the dewpoint temperature does not decrease as rapidly as does the air temperature. Eventually water vapour saturation is achieved and the cold sea fog forms in the thermal internal boundary layer.  相似文献   

Holocene environmental changes on the east coast of Korea     

Jungjae Park  Keun Bae Yu  Hyoun Soo Lim  Young Ho Shin 《Journal of Paleolimnology》2012,48(3):535-544

We present a record of Holocene environmental change on the east coast of Korea, inferred using pollen, carbon-isotopic composition (??¹³C), total organic carbon, total sulfur, carbon/nitrogen ratios, particle size analysis and major element geochemistry in a sediment core from Soonpogae Lagoon. A multi-proxy paleoenvironmental approach had not previously been applied in Korea and allowed us to reconstruct climate and vegetation change, sea-level rise, lagoon development, and human impact on the east coast of Korea over the last 8,000?years. Evidence from Soonpogae Lagoon supports the following three conclusions: (1) As a drying trend prevailed on the east coast of Korea after ~5,900?cal?yr BP, chemical weathering weakened and herbaceous plants became more important than during the previous humid phase (Holocene Climate Optimum), (2) Sea-level rise on the east coast slowed dramatically about 6,800?cal?yr BP, resulting in low rates of sedimentation in Soonpogae Lagoon, and (3) Soonpogae Lagoon was almost completely isolated from the sea by sand barriers when human impact intensified ~2,100 BP.  相似文献   

Applicability to Korean Marine Clay of the Mobilized Undrained Vane Shear Strength Using Correction Factors     

Ju Hyun Kim  Hiroshi Matsuda  Sang Guk Jeong 《Marine Georesources & Geotechnology》2013,31(2):150-159

The undrained shear strength normalized by the yield consolidation pressure, su/pc', is presented for four coastal sites: Busan/Gwangyang and Incheon/Gunsan, having the characteristics of high and low plasticity, respectively. The field vane shear strengths, su(FVT), were compared with unconfined compressive strength, qu/2 which has been used as a representative testing method in Korea. Many researchers have suggested that the undrained shear strength normalized by the yield consolidation pressure, su/pc', depends on Ip. However, the undrained shear strength normalized by the yield consolidation pressure, su/pc' is in the range of 0.25–0.35, independently of the plasticity index, Ip except for su/pc' using qu/2 values in the case of soils having a low plasticity, such as Incheon and Gunsan intermediate soils.

Bjerrum's correction factor has been commonly applied to evaluate mobilized undrained shear strength using the field vane test in Korea. However, the corrected undrained shear strengths using Bjerrum's correction factor, including Morris and Williams' method, were considerably underestimated for Korean marine clay when compared with the qu/2 values that have been used as the mobilized undrained shear strength for practical design in Korea.  相似文献   

Late quaternary paleoceanographic changes in the northeastern Ulleung Basin, East Sea, inferred from variations in biogenic components     

Yeon Jee Suh  Sangmin Hyun  Chanhong Park 《Ocean Science Journal》2013,48(3):289-300

Two piston cores (DD09-ST21, DD09-ST39B) from the northeastern Ulleung Basin in the East Sea were obtained to investigate variations in the biogenic components (calcium carbonate, organic carbon) and biogeochemical processes (δ¹³C and δ¹⁵N). The two cores had distinctive characteristics in terms of surface production, preservation and dissolution capacity of carbonate, and redox conditions of bottom-water. Core DD09-ST21 was characterized by an oxygen-depleted condition from 15 ka (MIS 2) to 60 ka (MIS 3). Core DD09-ST39B, on the other hand, showed oxic bottom-water conditions, possibly due to shallow water depth. These two cores with different redox condition showed opposite trends in terms of CaCO₃, TOC, and C₃₇ alkenone concentrations. CaCO₃ and C₃₇ concentrations were higher during the LGM in DD09-ST21 while lower contents were observed in DD09-ST39B in the same period. Moreover, consistently low TOC in DD09-ST39B and higher fluctuation of organic matters in DD09-ST21 may suggest difference in primary productivity, preservation capacity, or a potential dissolution effect. During the Holocene, the surface productivity of both cores increased, probably due to renewed ventilation and vertical mixing in the East Sea. Therefore, this study suggests spatial variation in production and preservation of biogenic components in the two cores since last 50 ka for DD09-ST39B and 80 ka for DD09-ST21 due to difference in environmental conditions such as water depth, bottom-water conditions, surface productivity and preservation.  相似文献   

Diurnal and spatial variabilities of monsoonal CG lightning and precipitation and their association with the synoptic weather conditions over South Korea     

Yu-Kyung Hyun  S. K. Kar  Kyung-Ja Ha  J. H. Lee 《Theoretical and Applied Climatology》2010,102(1-2):43-60

The spatial and temporal variations in cloud-to-ground (CG) lightning and precipitation during the summer monsoon months in Korea have been analyzed in relation to the regional synoptic weather conditions. The lightning data used in this study were collected from a lightning detection network installed by the Korean Meteorological Administration, while the precipitation data were collected from 386 Automatic Weather Stations spread over the entire Korean Peninsula during 2000 to 2001. A distinctive morning peak of precipitation is observed over the midwest region of Korea. Along the east coast, little precipitation and CG flash counts are found. Despite the strong afternoon peaks of convective rainfall due to the high elevation over the southern inland region, the south coast shows nocturnal or early morning peaks, which represents a common oceanic pattern of flash counts. In 2000, the nighttime peak for lightning counts dominates over the southern area, while the afternoon peak was strong in the midland during the summer, mainly due to the northward transportation of moisture to the Korean Peninsula. Conversely, the strong afternoon peak for the southern region was confronted with early morning peaks in the midwestern region during 2001. The eastward transport of moisture has been analyzed and was considered to be dominant in 2001. The study of several warm and cold type fronts in 2000 and 2001 indicate that the warm type fronts in 2000 were associated with very little lightning, while the cold type fronts appeared to be responsible for the occurrence of abundant lightning in 2001, thereby, indicating that the warm and cold type fronts were representative of the local lightning distribution in the respective years.  相似文献   

Uncertainty analysis using the WRF maximum likelihood ensemble filter system and comparison with dropwindsonde observations in Typhoon Sinlaku (2008)     

Hyun Hee Kim  Seon Ki Park  Dusanka Zupanski  Milija Zupanski 《Asia-Pacific Journal of Atmospheric Sciences》2010,46(3):317-325

In this study, the maximum likelihood ensemble filter (MLEF) is applied to a tropical cyclone case to identify the uncertainty areas in the context of targeting observations, using the WRF model. Typhoon Sinlaku (2008), from which dropwindsonde data are collected through THORPEX Pacific Asian Regional Campaign (TPARC), is selected for the case study. For the uncertainty analysis, a measurement called the deep layer mean (DLM) wind variance is employed. With assimilation of conventional rawinsonde data, the MLEF-WRF system demonstrated stable data assimilation performance over multiple data assimilation cycles and produced high uncertainties mostly in data-void areas, for the given tropical cyclone case. Dropwindsonde deployment through T-PARC turned out to occur inside or near the weak uncertainty areas that are identified through the MLEF-WRF system. The uncertainty analysis using the MLEF method can provide a guide for identifying more effective targeting observation areas.  相似文献   

Observation system experiments for Typhoon Jangmi (200815) observed during T-PARC     

Byoung-Joo Jung  Hyun Mee Kim  Yeon-Hee Kim  Eun-Hee Jeon  Ki-Hoon Kim 《Asia-Pacific Journal of Atmospheric Sciences》2010,46(3):305-316

In this study, the impact of various types of observations on the track forecast of Tropical Cyclone (TC) Jangmi (200815) is examined by using the Weather Research and Forecasting (WRF) model and the corresponding three-dimensional variational (3DVAR) data assimilation system. TC Jangmi is a recurving typhoon that is observed as part of the THORPEX Pacific Asian Regional Campaign (T-PARC). Conventional observations from the Korea Meteorological Administration (KMA) and targeted dropsonde observations from the Dropwindsonde Observations for Typhoon Surveillance near the Taiwan Region (DOTSTAR) were used for a series of observation system experiments (OSEs). We found that the assimilation of observations in oceanic areas is important to analyze environmental flows (such as the North Pacific high) and to predict the recurvature of TC Jangmi. The assimilation of targeted dropsonde observations (DROP) results in a significant impact on the track forecast. Observations of ocean surface winds (QSCAT) and satellite temperature soundings (SATEM) also contribute positively to the track forecast, especially two- to three-day forecasts. The impact of sensitivity guidance such as real-time singular vectors (SVs) was evaluated in additional experiments.  相似文献   

A comparative study for the fatigue assessment of a ship structure by use of hot spot stress and structural stress approaches     

Myung Hyun Kim  Seong Min Kim  Sung Geun Kim  Gyeong Rae Kim 《Ocean Engineering》2009,36(14):1067-1072

Recently, a mesh-size insensitive structural stress definition (Battelle structural stress method) has been proposed. This method gives a stress state at a weld toe with a relatively coarse mesh, such as up to 2t (t=plate thickness) or irregular mesh shapes. The structural stress definition is based on the elementary structural mechanics theory and provides an effective measure of a stress state in front of a weld toe. In this present study, a fatigue strength assessment was carried out for a side shell connection of a container vessel using both the hot spot stress and the structural stress methods. A consistent approach to computing extrapolated hot spot stress for design purposes based on converged hot spot stresses is described and current fatigue guidance is evaluated. Fatigue strength predicted by the two methods, i.e. hot spot stress and structural stress approaches, at hot spot locations of a typical ship structure are compared and discussed.  相似文献