• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1997.10a
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• pp.57-69
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• 1997

All of the Tsumami which affected severly the east coast of the Korean Peninsula in the years 1741-1993 are caused by earthquakes occurred along the boundary sea of Japan and norther Honshu. These earthquakes with magnitude greater than 7.0 are results of relative movement between the North American Plate and Urasian Plate. The active fault along the boundary of the two plates is attracted by many researchers since the 1983 May earthquake of magnitude 7.7. It is important to anticipate when the next large earthquake will occur and how much it affect the east coast of Korea. Among a few models of spatial seismic gap were proposed for earthquake occurrences accompanying Tsunami, Ishikawas' east-west seismic gap model is the most probable one. There is a tendency that the period between the activities of the active faults becomes shorter. It is expected that a large earthquake of magnitude 7.0 or above will occur along the eastern boundary of Japan Sea at the end of this century and produce Tsunami at the east coast of Korea.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.24 no.4
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• pp.509-518
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• 2019

Analyses with various Sea Surface Temperature (SST) products indicate that the interannual variability of the area-averaged SST in the East/Japan Sea (EJS) is well correlated to that of Pacific Decadal Oscillation (PDO) during 1979-2018, especially in the autumn. The regression analysis with the wind vectors at 200 hPa, where the strongest jet stream flows, suggests that the long-term variability of the intensity as well as the meridional movement of the jet stream are related to the coupling of the autumn EJS SST and PDO. When the axis of the jet stream moves poleward (equatorward) with its weakening (strengthening), both the EJS SST and North Pacific SST increase (decrease). This suggests that both the intensity and meridional movement of the jet stream are possibly related to the coupling of the autumn EJS SST and PDO. However, effects of a weak jet stream during the summer and the strong East Asian winter monsoon make weak coupling between the EJS SST and PDO.

• Journal of the korean society of oceanography
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• v.35 no.4
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• pp.192-199
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• 2000

Standard CTD data processing recommended by Sea-Bird Electronics produced thermal-lag corrections larger than 0.1 psu for the data taken during the CREAMS expeditions in the northern part of the East/Japan Sea where a vertical temperature gradient frequently exceeds 1.0$^{\circ}$C/m in the upper 100 m near the sea surface. As the standard processing is based upon a recursive filter which was introduced by Lueck and Pickle (1990), coefficients of the recursive filter have been newly derived for the CREAMS data by minimizing the difference between salinities of downcast and upcast in temperature-salinity domain. The new coefficients are validated by comparison with salinities measured by a salinometer, AUTOSAL 8400B. An accurate correction for the thermal-lag is critical in identifying water masses at intermediate depth in the East/japan Sea.

• Journal of Environmental Science International
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• v.12 no.3
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• pp.257-263
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• 2003

Oceanographic features around Korean waters related to the global change were studied by analysis of the longterm variation of water temperature, dissolved oxygen, sea level of the surface layer with 1$^{\circ}C$ temperature, spatial position of the subpolar front in the East Sea/Japan Sea (the East sea hereafter) and the Wolf Sunspot Number. With the global warming, the temperature of Korean waters has been increased 0.5∼1.0$^{\circ}C$ for 33years (1968∼2000). In case of the dissolved oxygen in the East Sea has been decreased 0.46$m\ell$/$\ell$. Year to year vertical fluctuations of the monthly anomalies of the surface layer with 1$^{\circ}C$water in the East Sea have predominant periods with 15years as the longterm variation of Arctic climate, 12 and 18years as the El Nino-Southern Oscillation. Spatial position of the subpolar front in the East Sea moved to northern part of the sea from the southern part of the sea with the increasing sea surface temperature. The relationship between the number of Wolf Sunspot and the anomalies of sea surface temperature was very closer after the late of 1980s than those before the early of 1980s in Korean waters.

• Animal Systematics, Evolution and Diversity
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• v.30 no.2
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• pp.144-150
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• 2014

Two species of hippolytid shrimps, Eualus kuratai Miyake and Hayashi, 1967 and Heptacarpus igarashii Hayashi and Chiba, 1989, were collected at a sea cucumber farm from the East Sea. These species are described and illustrated for the first time in Korea. Eualus kuratai is closely related to E. middendorffi; however, it lacks a dorsomedian spine on the fourth and fifth abdominal somites. Heptacarpus igarashii can be easily distinguished from other Korean Heptacarpus species due to its short rostrum that lacks ventral teeth on margin. This report extends the previously known ranges from Japan and Korea. In Korea, both genera, Eualus and Heptacarpus, have seven species according to the present report, respectively; moreover, hippolytid shrimps now consist of 31 species of nine genera.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.29 no.3
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• pp.183-190
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• 1993

A cooperative Korea-Japan investigation for the demersal fisheries resources of the East China Sea carried out by using the training ship Oshoro Maru belong to Hok-kaido University, Japan, during 1-8 November, 1991. The research vessel sampled 15 stations with demersal trawls on the East China Sea, and 1,364 nautical miles of track line were surveyed hydroacoustically. The hydroacoustic observations were taken with a scientific echo sounder operating at two frequencies of 25 kHz and 100 kHz, and a microcomputer-based echo integrator. Fish samples were collected by demersal trawling, and temperature, salinity and dissolved oxygen were measured with a CTD system. The target strength of fish school was estimated from the relationship between mean scattering strength and catches caught by demersal trawling. The results obtained can be summarized as follows: 1. The mean backscattering strength for 15 layers occupied by demersal trawls at 25 kHz ranged from -70.4 dB to -59.1 dB. Then the catch per one hour ranged from 8.2 to 587.5 kg/hour. 2. The mean backscattering strength for the entire layer between transducer and seabed in the survey area of the East China Sea at 25 kHz and 100 kHz were -68.0 dB and -73.1 dB, respectively. 3. The mean fish-school target strength per one kilogram at 25 kHz and 100 kHz were -28.3 dB/kg, and -30.4 dB/kg, respectively.

• Journal of Environmental Science International
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• v.22 no.10
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• pp.1363-1371
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• 2013

In this study, we estimate the interannual spatial and temporal distributions of fishing grounds at night in the East Sea based on satellite and in-situ data. We observe that the $15^{\circ}C$ thermal front moves in the north-south direction according to the movement of the warm water (above $18^{\circ}C$) in the Tsushima Warm Current (TWC) area, forcing the cold water area (below $10^{\circ}C$) to either expand or shrink. The interannual variations of sea surface temperature (SST) in winter represented by the indicator SST of $6^{\circ}C$ are consistent with the east-west zonal areas in the central East Sea which represented over $1^{\circ}C$ standard deviation of SST in February during 1990-2000. Annual SST in the fishing grounds of common squid fishing vessels, observed both by fishing vessels and satellites range from 9-$22^{\circ}C$, with the satellite-observed data having a larger range than the fishing vessel-based ones. The interannual distributions of the common squid fishing grounds in the East Sea are mostly concentrated in the TWC area in the southwestern part of the East Sea and in the coast of southern Honshu and Hokkaido in Japan. The interannual distributions of the nighttime fishing vessels are consistent with the catches investigated from the fishing vessel.

• Animal Systematics, Evolution and Diversity
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• v.30 no.2
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• pp.132-136
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• 2014

Five sea cucumbers were collected from Gisamun and Gonghyeonjin of Gangwon-do, in the East Sea, Korea from 27 December 2009 to 14 November 2012. These specimens were classified as Synallactes nozawai Mitsukuri, 1912 belonging to the family Synallactidae of order Aspidochirotida based on morphological characteristics. The family, genus and species are recorded for the first time from Korea. The distinct morphological characteristics of this species are as follows: body flexible, with thin gelatinous body wall; presence of numerous tubercles along dorsal ambulacra table of body wall consisted of three- or four-armed disk and a spire-form pillar. This species usually inhabits the deep sea and is distributed in the Northwest Pacific from northern Japan to Bering Sea.

• 한국방재학회:학술대회논문집
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• 2007.02a
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• pp.327-331
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• 2007

23 tropical cyclones of tropical storm(TS) intensity or higher formed in the western North Pacific and the South China Sea in 2006. The total number is less than the 30-year $(1971{\sim}2000)$ average frequency of 26.7, Out of 23, 15 cyclones reached typhoon(TY) intensity, three severe tropical storm(STS) intensity, and five TS intensity. The tropical cyclone season in 2006 began in May with the formation of CHANCHU(0601). While convective activity was slightly inactive around the Philippines from late June to early August. In addition, subtropical high was more enhanced than normal over the south of Japan from May to early August. Consequently, most tropical cyclones formed over the sea east of the Philippines after late June, and many of them moved westwards to China. CHANCHU(0601), BILIS(0604), KAEMI(0605), PRAPIROON(0606) and SAOMI(0608) brought damage to China, the Philippines, and Vietnam. On the other hand, EWINIAR(0603) moved northwards and hit the Republic of Korea, causing damage to the country From late August to early September, convective activity was temporarily inactive over the sea east of the Philippines. However, it turned active again after late September. Subtropical high was weak over the south of Japan after late August. Therefore, most tropical cyclones formed over the sea east of the Philippines and moved northwards. WUKONG(0610) and SHANSHAN(0613) hit Japan to bring damage to the country. On the other hand, XANGSANE(0615) and CIMARON(0619) moved westwards in the South China Sea, causing damage to the Philippines, Thailand, and Vietnam. In addition, IOKE(0612) was the first namded cyclone formed in the central North Pacific and moved westwards across longitude 180 degrees east after HUKO(0224).

• Journal of the Korean earth science society
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• v.42 no.4
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• pp.401-411
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• 2021

This study provides comprehensive assessment results for the most recent high-resolution regional climatology in the East/Japan Sea by comparing with the various existing climatologies. This new high-resolution climatology is generated based on the Optimal Interpolation (OI) method with individual profiles from the World Ocean Database and gridded World Ocean Atlas provided by the National Centers for Environmental Information (NCEI). It was generated from the recent previous study which had a primary focus to solve the abnormal horizontal gradient problem appearing in the other high-resolution climatology version of NCEI. This study showed that this new OI field simulates well the meso-scale features including closed-curve temperature spatial distribution associated with eddy formation. Quantitative spatial variability was compared to the other four different climatologies and significant variability at 160 km was presented through a wavelet spectrum analysis. In addition, the general improvement of the new OI field except for warm bias in the coastal area was confirmed from the comparison with serial observation data provided by the National Fisheries Research and Development Institute's Korean Oceanic Data Center.